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QP44  .P31  Laboratory  exercises 


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LABORATORY  EXERCISES 


IN 


ANATOMY  AND    PHYSIOLOGY 


BY 


JAMES   EDWARD   PEABODY,    A.M. 

Instructor  in  Biology  'in  the 
High  School  for  Boys  and  Girls,  New  York  City 


NEW  YORK 

HENRY  HOLT   AND   COMPANY 
1898 


T5| 


Copyright,  1898, 

BY 

HENRY  HOLT  &  CO 


ROBRRT   nRtTMMONn,    PRINTKR,    NRW   YORK. 


PKEFACE. 

Every  pupil  in  the  study  of  human  physiology 
should  be  led  to  see  that  most  of  the  materials  re- 
quired for  observation  and  experiment  in  this  subject 
are  furnished  by  the  organs  and  tissues  of  his  own 
body.  The  following  laboratory  directions  aim  pri- 
marily to  familiarize  the  pupil  with  the  working  of  his 
own  organs  of  motion,  circulation,  respiration,  and  di- 
gestion. Much  of  the  necessary  supplementary  ma- 
terial (soup-bones,  meat,  foods,  etc.)  can  be  easily 
obtained  by  the  student.  The  pieces  of  apparatus 
needed  for  the  class  demonstrations  and  experiments 
(test-tubes,  bell-jars,  thistle-tubes)  are  usually  found 
in  the  chemical  or  physical  laboratory  of  the  school. 

At  the  beginning  of  each  topic  of  study  I  have  given 
directions  which  in  my  experience  have  been  found 
necessary  to  guide  the  pupil  in  his  observations  and 
experiments.  The  questions  which  follow  these  direc- 
tions have  been  framed  with  the  object  of  leading  the 
student  to  seek  the  facts  from  the  material  itself.  The 
student  should  be  trained  especially  to  distinguish  in 
the  experiments  observed  results  from  the  inferences 
that  may  be  drawn  from  those  results. 

I  have  found  that  a  considerable  amount  of  labora- 
tory work  may  be  most  profitably  done  by  the  pupil 

iii 


iv  PBEFAGE, 

at  home  and  reported  in  class  at  tlie  next  recitation 
period.  This  is  especially  true  in  the  study  of  foods, 
yeast,  and  bacteria.  Iodine  and  Fehling  solution  are 
furnished  the  pupil  and  test-tubes  are  loaned.  We 
have  found  that  four  fifths  of  the  test-tubes  are  re- 
turned uninjured.  In  the  pages  that  follow  I  have 
marked  thus  ^  the  exercises  adapted  for  home  study. 
The  mark  t  indicates  a  demonstration  before  the 
class  by  the  teacher.  The  remaining  exercises  (un- 
marked) would  best  be  performed  by  each  pupil  in 
the  laboratory  under  the  direction  of  the  teacher. 

The  following  method  of  recording  the  laboratory 
observations  has  been  found  to  work  successfully. 
The  observations  and  conclusions  are  briefly  recorded 
by  the  pupil  in  his  note-book  as  the  work  is  done. 
Some  little  time  is  taken  for  discussion  at  the  close  of 
the  period,  when  the  facts  are  clearest  in  mind,  special 
care  being  taken  to  see  that  correct  inferences  have 
been  drawn.  That  the  work  of  the  day  may  be  more 
firmly  fixed  in  the  mind  of  the  pupil  he  is  required  to 
write  on  paper  of  a  certain  kind  and  size  and  present 
at  the  next  lesson  a  carefully  prepared  statement  of 
(1)  the  steps  in  the  experiment,  (2)  the  results  ob- 
served, (3)  the  conclusions  which  were  drawn  from 
the  experiment.  These  papers,  together  with  the 
drawings  and  other  work  prepared  in  class,  are  ar- 
ranged in  a  cover  belonging  to  each  pupil,  and  consti- 
tute his  laboratory  book. 

The  descriptive  terms  dorsal  and  ventral,  anterior 
and  posterior,  median  and  lateral,  employed  in  com- 
parative anatomy,  are  used  in  the  following  directions, 
since   they  seem   preferable    to    the    more   indefinite 


PREFACE.  V 

terms  front  and  back,  upper  and  lower,  middle  and 
side,  commonly  used  in  books  on  human  physiology. 
I  have  adopted  throughout  the  food  study  the  term 
nutrients  (for  food-materials,  food-stuffs),  and  nitrog- 
enous substances  (for  proteids,  albuminoids,  gelati- 
noids,  etc.) ;  these  terms  are  used  in  the  publications 
of  the  U.  S.  Department  of  Agriculture. 

I  have  found  the  study  of  the  material  at  the  Amer- 
ican Museum  of  Natural  History  (especially  the  skele- 
tons and  teeth  of  mammals)  a  valuable  means  of  review 
and  of  awakening  interest  in  the  subject.  With  a  defi- 
nite list  of  questions  (see  p.  73)  in  the  hands  of  each 
pupil  a  division  of  thirty  to  fifty  can  be  directed  in 
this  work.  Time  should  be  taken  at  the  close  of  such 
study  for  a  comparison  of  notes  and  for  general  dis- 
cussion. 

Some  knowledge  of  the  cell  is  so  essential  to  any 
intelligent  comprehension  of  the  subject  of  human 
physiology  that  it  seems  necessary  to  introduce  fre- 
quent discussions  of  protoplasm  and  its  properties. 
Circulating  protoplasm  is  easily  demonstrated  in  the 
cells  of  the  plant  Nitella.  Epithelium  (including 
gland  and  ciliated),  muscle  and  nerve  cells  should  be 
shown  if  possible.  The  study  of  yeast  and  bacteria  is 
suggested  to  give  the  pupil  some  acquaintance  with 
the  physiology  of  the  cell,  as  well  as  a  knowledge  of 
these  organisms. 

Since  physiology  unfortunately  precedes  physics  and 
chemistry  in  the  ordinary  High  School  courses  of 
study,  it  is  necessary  to  give  the  pupil  some  idea  of 
the  fundamental  principles  of  these  subjects.  It  seems 
wise  to  discuss  oxidation  and  its  products  more  or 


vi  PBEFAGE. 

less  thoroughly.  The  structure  and  physiology  of 
the  organs  of  special  sense  (eye,  ear),  as  well  as  the 
thorough  consideration  of  levers,  should  be  omitted, 
in  my  judgment,  until  after  a  course  in  physics  has 
been  taken. 

It  is  not  expected  that  all  of  the  following  experi- 
ments will  be  performed  in  the  limited  time  usually 
assigned  in  the  curriculum  to  this  subject.  The  exer- 
cises are,  however,  sufficiently  varied  to  allow  a  wide 
range  of  choice.  The  laboratory  work  on  a  given 
topic  should  if  possible  be  given  before  the  study  of 
that  topic  in  the  text-book. 

The  teacher  will  find  the  following  reference-books 
to  be  valuable  in  experimental  physiology:  Stirling's 
"  Outlines  of  Practical  Physiology,"  (P.  Blakiston, 
Son  &  Co.,  Philadelphia) ;  Foster  and  Langley's 
"  Practical  Physiology"  (The  Macmillan  Co.,  N.  Y.) ; 
Klein's  "Micro-Organisms  and  Disease"  (The  Mac- 
millan Co.,  N.  Y.).  Additional  exercises  are  suggested 
in  ''  Outlines  of  Requirements  in  Anatomy,  Physiol- 
ogy, and  Hygiene"  (Harvard  University). 

Suggestions  for  many  of  the  following  exercises 
were  found  in  the  publications  of  J.  Y.  Bergen,  B.  P. 
Colton,  H.  Newell  Martin,  H.  P.  Bowditch,  M.D.,  and 
in  the  books  mentioned  above.  The  outline  for  the 
study  of  bacteria  was  suggested  by  Dr.  T.  M.  Prud- 
den,  College  of  Physicians  and  Surgeons,  N.  Y.  The 
experiments  with  the  joint  apparatus  ( 8 )  were 
adapted  from  the  "Harvard  Requirements,"  by  Dr. 
G.  W.  Fitz  of  Harvard  University,  who  devised  the 
apparatus.  Many  valuable  suggestions  have  been 
given  by  Dr.  C.  B.  Davenport  of  Harvard  University. 


PREFACE.  VU 

I  am  especially  indebted  to  Dr.  Margaret  B.  Wilson 
of  the  N.  Y.  Normal  College  for  carefully  revising  my 
manuscript. 

J.  E.  P. 
High  School  for  Boys  and  Girls, 
New  York  City,  July  13,  1898. 


TABLE   OF   CONTENTS. 

I.  The  Skeleton  and  Muscles. 

PAGE 

1.  Structure  of  Bones 1 

2.  Composition  of  Bones 2 

3.  Classification  of  Bones 4 

4.  Study  of  Muscles ; 4 

5.  Study  of  Lean  Meat  (Muscle) 8 

6.  Structure  of  a  Joint 9 

7.  Study  of  tlie  Joints  in  tlie  Body 11 

8.  Experiments  with  Joint  Apparatus 13 

II.  Foods. 

9.  Acid  and  Alkaline  Reactions 17 

10.  To  Determine  tlie  Amount  of  Water  in  Foods 18 

11.  To  Test  Foods  for  Starch 19 

13.  To  Test  Foods  for  Grape-sugar 20 

13.  To  Test  Foods  for  Nitrogenous  Substances 22 

14.  To  Test  Foods  for  Fats  and  Oils 24 

15.  To  Test  Foods  for  Mineral  Substances 24 

16.  The  Analysis  of  Flour 25 

17.  The  Study  of  Milk 26 

III.  The  Processes  op  Digestion  and  Absorption. 

18.  The  Study  of  the  Mouth 29 

19.  To  Prepare  Artificial  Digestive  Juices 31 

20.  The  Digestion  of  Starch 32 

21.  The  Digestion  of  Mineral  Substances 33 

22.  The  Digestion  of  Nitrogenous  Substances 34 

23.  The  Digestion  of  Fats 36 

24.  The  Principles  of  Osmosis 39 

25.  Outline  for  Recording  the  Digestion  of  Nutrients. . .  42 

ix 


X  TABLE    OF   CONTENTS. 

IV.  The  Blood  and  •  Ciroiilation. 

PAGE 

26.  Composition  of  the  Blood 4a 

37.  Change  in  the  Blood  after  Mixing  with  Oxygen 44 

28.  Microscopic  Study  of  Blood-corpuscles 44 

29.  Study  of  the  Heart 45 

30.  Circulation  of  the  Blood  in  the  Tail  of  the  Tadpole.  46 

31.  The  Pulse  in  the  Pupil's  own  Body 47 

V.  Oxidation  and  its  Products. 

32.  Properties  of  Carbon 48 

33.  Tests  for  Carbon  Dioxide 48 

34.  Temperature  of  the  Body 49 

VI.  Respiration. 

35.  Action  of  the  Diaphragm  and  Lungs 50 

36.  Circulation  of  the  Air  in  the  School-room 51 

37.  Inspired  and  Expired  Air , . .  52 

VII.  The  Skin. 

38.  Study  of  the  Skin 53 

VIII.  Excretion. 

39.  Study  of  the  Kidney 56 

40.  Study  of  Excretion 58 

IX.  Nervous  System. 

41.  Sensations  of  Touch 58 

42.  Sensations  of  Taste  and  Smell 60 

X.  Supplementary  Work. 

43.  Study  of  Yeast 62 

44.  Study  of  Bacteria 67 

45.  Comparative  Study  of  the  Mammalian  Skeleton. ...  73 

XI.  Rules  for  the  Use  of  the  Compound  Microscope..  75 
XII.  List  of  Apparatus  and  Chemicals  for  a  Class  of  24..  79 


LABORATORY  EXERCISES 

IN 

ANATOMY  AND   PHYSIOLOGY. 
1.    Strtjctuee  of  Bones. 

Materials  :  A  clean  rib  of  lamb  or  pork  cut  smoothly  across  the 
end  ;  two  clean  soup-bones,  one  sectioned  transversely,  the  other  di- 
vided into  halves  lengthwise.  (After  completing  the  study  of  the 
structure,  lay  aside  the  bones  for  the  experiments  in  2.) 

A.  Structure  of  a  soup-bone  (long  bone). 

1.  Study  of  cross-section  of  a  long  bone. 

a.  In  what  respects  is  the  layer  of  bone- 
tissue  which  covers  the  outside  dis- 
tinguishable from  the  tissues  within? 

h.  How  is  the  bone-tissue  arranged  within 
this  outside  layer? 

c.  What  is  the  consistency  of  the  marrow 
which  fills  the  spaces  in  the  bone- 
tissue  ? 

d.  How  does  the  color  of  the  marrow  in  the 
marrow-cavity  differ  from  the  color  of 
the  spongy  bone?  Can  you  suggest 
any  reason  for  this  difference  ? 

e.  Make  a  diagrammatic  drawing  of  the 
cross-section  of  the  bone  magnified 
twice  (X  2),  labelling  hard  bone, 
spongy  bone,  marrow. 


2  LABORATORY  EXERCISES. 

2.  study  of  longitudinal  section  of  a  long  bone. 

a.  Identify  all  the  structures  seen  in  cross- 
section,  yiz.,  hard  bone,  spongy  bone, 
marrow. 

h.  What  additional  facts  in  regard  to  the 
structure  of  a  long  bone  do  you  learn 
from  the  longitudinal  section  ? 

c.  Make  a  drawing  of  the  longitudinal  sec- 
tion,   labelling     as    in    the    previous 
drawing. 
B.  Structure  of  a  rib  (tabular  bone). 

1.  Can  you  distinguish    in  the  cross-section  of 

the  rib  the  hard  bone,  spongy  bone,  and 
marrow  ? 

2.  How  do  long  bones  and  tabular  bones  differ 

in  plan  of  structure  ? 

3.  Make  a  diagrammatic  drawing  of  the  cross- 

section  of  the  rib  (X  2),  labelling  all  the 
parts. 


2.   Composition  of  Bones.* 

Materials:  Two  clean  ribs  ;  the  two  halves  of  the  soup-bone  used 
in  1  ;  diluted  hydrochloric  acid  (6  parts  water  to  1  part  acid) ;  weigh- 
ing balances  ;  a  piece  of  wire. 

A.  Action  of  acid  on  bone. 

Compare  the  two  ribs  as  to  form  and  size  ; 
place  one  of  them  in  a  bottle  of  diluted  muriatic 
acid.  Allow  the  bone  to  remain  in  the  acid  for 
a  few  days  and  then  compare  the  two  ribs  again. 

*  This  exercise  may  be  performed  by  the  pupil  at  home. 


COMPOSITION    OF  BONES.  3 

1.  Has  the  acid  clianged  the  form  of  the  bone  ? 

2.  Has  it  changed  the  size  of  the  bone  ? 

3.  What  change  do  you  observe  to  have  taken 

place  ? 

4.  Pour  some  of  the  liquid  in  which  the  bone 

has  been  soaking  into  an  evaporating-dish 
and  heat  over  an  alcobol-lamp  or  over  a 
gas-flame  until  the  liquid  has  disappeared. 
What  kind  of  substance  is  left  in  the  dish  ? 
(This  substance  is  a  kind  of  mineral  matter 
formed  from  the  mineral  matter  of  the  bone 
by  the  action  of  the  acid.) 

5.  What  properties  of  bone  are  due  to  the  pres- 

ence of  mineral  matter  ? 
B.  Effect  of  burning  bone. 

Weigh  half  of  the  long  bone  used  in  1.  Tie  a 
piece  of  wire  about  it  and  place  it  in  a  hot  coal 
fire.  Allow  it  to  remain  for  a  half-hour  and  then 
remove  it  carefully  by  means  of  the  wire. 

1.  Write  in  your  note  book  a  brief  account  of 

all  the  changes  which  you  observed  while 
the  bone  was  in  the  fire. 

2.  Has  the  bone  been  changed  in  form  or  size  ? 

3.  What  change  can  you  see  in  the  bone  ? 

4.  What  part  of  the  bone  has  been  most  affected 

bv  the  fire  ? 

5.  Try  to  break  the  bone ;  what  is  the  use  in 

bone  of  the  substance  which  has  been  lost? 

6.  Weigh  the  bone  and  determine  what  per  cent 

of  the  original  bone  remains  as  ash  (mineral 
matter)  and  what  per  cent  has  disappeared 
(animal  matter). 


4  .  LABORATORY  EXERCISES, 

0.  Effect  of  boiling  bones  in  water. 

Place  the  other  half  of  the  soup-bone  in  a  pint 
of  water  and  allow  it  to  simmer  on  the  back  of 
the  stove  for  4  to  6  hours.  Strain  the  liquid 
through  a  cloth  and  allow  it  to  cool. 

1.  Describe  the  substance  which  is  obtained. 

2.  Set  aside  a  small  portion  of  this  *'  soup-stock  " 

to  test  it  later  for  nutrients. 


3.  Classification  of  Bones. 

From  the  articulated  skeleton  make  lists  of 

1.  Long  bones  (distinguished  bj  shaft  and  artic- 

ular extremities  or  heads). 

2.  Short  bones. 

3.  Tabular  or  flat  bones. 

4.  Irregular  bones. 


4.   Study  of  the  Muscles.* 

Definitions. 

1.  The  part  of  the  muscle  which  contracts  is  the 

helly;  the  bands  or  cords  at  the  ends  are  the 
tendons. 

2.  The  end  of  the  muscle  which  moves  least  is 

called   the  origin;    the  part  which  moves 
most,  the  insertion. 

3.  Muscles  which  bend  or  flex  the  limb  are  called 

flexors ;  muscles  which  straighten  or  extend 
the  limb,  extensors. 


STUDY   OF    THE   MUSCLES.  5 

A.  The  biceps  muscle. 

1.  Clasp  the  front  of  the  right  upper  arm  with 

the  left  hand ;  draw  up  or  flex  the  right  fore- 
arm as  far  as  possible.  What  changes  do 
you  notice  in  the  belly  of  the  muscle  ? 

2.  Span  the  biceps  muscle  of  the  right  arm  by 

placing  the  tips  of  the  fingers  of  the  left 
hand  at  the  angle  of  the  elbow  in  front  and 
the  thumb  as  far  Up  on  the  arm  as  pos- 
sible ;  again  flex  the  right  forearm.  What 
changes  in  the  muscle  other  than  those  al- 
ready enumerated  do  you  notice  ? 

3.  Roll  up  the  sleeve  as  far  as  j)ossible.     With 

a  tape-measure  get  the  circumference  of 
the  upper  arm  when  it  hangs  free,  and 
again  when  the  forearm  is  strongly  flexed. 
Write  down  your  results. 

4.  Place  the  fingers  of  the  left  hand  at  the  angle 

in  front  of  the  elbow  of  the  right  arm ;  flex 
and  extend  the  right  forearm  several  times. 
Note  the  cord  or  tendon  at  the  lower  end 
of  the  biceps  muscle.  To  which  of  the 
bones  of  the  forearm  does  it  seem  to  be 
attached  ? 

5.  Determine  if  possible  by  moving  the  forearm 

the  bones  to  which  the  upper  end  of  the 
biceps  is  attached. 

6.  Find  on  the  articulated  skeleton  in  class  the 

rough  prominences  to  which  the  tendons  of 
this  muscle  are  attached. 

B.  The  triceps  muscle. 

1.  Clasp  the  back  of  the  right  upper  arm  with  the 


6  LABORATORY   EXERCISES. 

left  band  ;  forcibly  straigbten  or  extend  tbe 
rigbt  forearm.  Locate  tbe  belly  of  tbe 
triceps  witb  reference  to  tbe  belly  of  tbe 
biceps.  Locate  botb  muscles  witb  refer- 
ence to  tbe  bnmerus. 
2.  By  flexing  and  extending  tbe  forearm  deter- 
mine tbe  position  of  tbe  lower  tendon  of 
tbe  triceps.  To  wbicb  bone  of  tbe  forearm 
is  it  attacbed  ? 
C.  Tbe  flexor  muscles  of  tbe  fingers  and  of  tbe  tbumb. 

1.  Clasp  tbe  front  side  of  tbe  rigbt  forearm  near 

tbe  elbow ;  clencli  tbe  band  quickly  and 
forcibly.  Locate  tbe  belly  of  tbis  flexor 
muscle  witb  reference  to  tbe  bones  of  tbe 
forearm. 

2.  Press  tbe  forefinger  and  tbumb  strongly  to- 

getber.  Wbat  cbange  is  noticed  in  tbe 
tbick  mass  of  muscle  at  tbe  base  of  tbe 
tbumb  ?  Along  wbat  bone  does  tbe  flexor 
muscle  of  tbe  tbumb  lie  ? 

3.  Measure    tbe    circumference    of   tbe  forearm 

wben  tbe  band  is  open,  and  again  wben  it  is 
tigbtly  closed.  Record  your  results.  Com- 
pare witb  figures  for  biceps. 

4.  Flex  tbe  fingers  and  note  tbe  movements  of 

tbe  tendons  in  tbe  wrist.  Along  wbat  bones 
do  tbese  tendons  pass  ? 

5.  Wbat  would  be  tbe  form  of  tbe  band  if  tbe 

flexor  muscles  of  tbe  fingers  were  located 
in  a  position  corresponding  to  tbe  flexor 
muscle  of  tbe  tbumb  ?  "Wbat  is  gained  by 
placing  tbese  muscles  in  tbe  forearm  ? 


STUDY   OF   THE   MUSCLES.  7 

D.  The  extensor  muscles  of  the  fingers. 

1.  Straighten  back  the  fingers  as  far  as  possible 

and  by  feeling  of  the  back  of  the  forearm 
locate  the  belly  of  the  extensor  muscles  of 
the  fingers. 

2.  Move  the  middle  finger  alone.     Describe  the 

movements  of  the  tendons  on  the  back  of 
the  hand. 

3.  Flex  the  middle  finger  of  each  hand  until  it 

touches  the  palm  of  the  hand ;  place  the 
two  hands  together  (palms  facing)  so  that 
the  tips  of  the  forefingers,  fourth  fingers, 
and  little  fingers  touch,  pressing  the  backs 
of  the  middle  fingers  closely  together.  Try 
to  separate  each  of  the  pairs  of  fingers,  still 
keeping  the  middle  fingers  pressed  together. 
Explain  result. 

E.  The  muscles  which  move  the  ankle. 

1.  Stand  on  tiptoe  and  locate  in  the  calf  of  the 

leg  the  belly  of  the  extensor  muscles  of 
the  foot  which  cause  this  movement.  To 
which  bone  is  the  lower  tendon  of  this 
muscle  (tendon  of  Achilles)  attached  ? 

2.  Determine  the  position  of  the  flexor  muscle 

of  the  foot  by  flexing  the  ankle  as  far  as 
possible.  Which  is  the  larger,  the  flexor 
or  the  extensor  ?     Why  ? 

F.  The  jaw-muscles. 

Alternately  close  the  jaws  tightly  together  and 
open  them.  Find  the  muscles  which  cause 
these  movements.  Watch  in  the  glass  and 
describe  the  movements  of  these  muscles. 


8 


LABORATOBT  EXERCISES, 


Fill  out  in  your  note-book  a  table  like  the  following  : 


Name  of  muscle. 

Origin  at- 
tached to  what 
bone  or  bones. 

Belly  opposite 
what  bone 
or  bones. 

Insertion  at- 
tached to  what 
bone  or  bones. 

Biceps 

Triceps 

Flexor  muscles  of  fingers. . . 
Extensor  muscles  of  fingers. 

Flexor  muscles  of  foot 

Extensor  muscles  of  foot.. . 

5.  Study  of  Lean  Meat  (Muscle). 

Materials  :  Slices  of  meat  from  tlie  shank  of  beef  aboulT  an  incli 
tliick.  Cut  the  slices  into  blocks  about  a  half-incL.  square.  The 
structure  is  more  clearly  seen  if  the  meat  is  allowed  to  dry  in  the  air 
for  a  few  hours.  Dissecting  needles,  slide  and  cover  glass,  com- 
pound microscope  \"  objective. 


A.  Gross  structure  of  muscle. 

1.  What  is  the  shape  of  the  small  bundles  (fas- 

ciculi) of  which  the  muscle  is  composed? 
Do  all  of  the  bundles  appear  of  the  same 
shape  when  seen  in  cross-section  ? 

2.  What  are  the  characteristics  of  the  material 

surrounding  the  bundles  (perimysium)  ? 

3.  Can  you  distinguish  any  fat  in  the  piece  of 

meat  which  you  are  studying  ?  If  so,  where 
is  it  situated  ? 

4.  Is  tendon  present  ?  ' 

5.  Make  a  drawing  of  the  piece  of  muscle  show- 

ing cross  and  longitudinal  sections  (X  5). 
Label  bundles,  perimysium,  and  fat  and 
tendons  if  present. 


8TUCTURE    OF  A    JOINT.  9 

B.  Microscopic  structure  of  muscle. 

Separate  with  dissecting  needles  a  small  por- 
tion of  the  muscle ;  cover  it  with  water  and  tear 
it  apart  with  the  needles  until  you  have  the 
smallest  portion  of  the  bundle  which  you  can 
get.  Place  this  bit  of  muscle  on  a  glass  slide, 
add  a  drop  of  water,  and  tease  it  out  with 
needles  ;  cover  with  glass  and  examine  under 
the  high  power  of  the  compound  microscope. 

1.  Of   what   is   the    piece   of   muscle    found   to 

consist  ? 

2.  Why  is  this   kind  of  muscle  called  striped 

muscle  ? 

3.  Draw   a    muscle-bundle    as   seen    under   the 

microscope.     Label  fibres,  cross-stripes. 

6.  Structure  of  a  Joint. 

Materials :  Fresh,  leg- joint  of  lamb  or  veal ;  scalpel. 

A.  Movement  at  the  joint. 

1.  Holding  one  of  the  bones  in  a  fixed  position, 

in  how  many  directions  can  the  other  bone 
be  moved  ? 

2.  Why  is  the  joint  immovable  in  other  direc- 

tions ? 

B.  Muscles  and  tendons. 

1.  Dissect  away  the  muscle  with  the    scalpel ; 

by  what  are  the  muscles  attached  to  the 
bones? 

2.  Try  to  stretch  or  break  these  cords  (tendons) ; 

what  properties  of  tendons  does  this  dem- 
onstrate ? 


10  LABORATORY   EXERCISES. 

3.  What  is   the   advantage   of   the   absence    of 
muscle -tissue  over  joints  ? 

C.  Ligaments. 

1.  What  kind  of  tissue  holds  the  bones  together 

after  the  muscle  is  removed? 

2.  How  is  this  tissue  attached  to  bone  so  as  to 

allow  movement  at  the  joint  ? 

D.  Joint- cavity. 

1.  Cut  through  the  ligaments  with  a  scalpel  so 

as  to  open  the  joint-cavity  ;  what  is  the 
appearance  of  the  liquid  within  (synovial 
fluid)? 

2.  Suggest  the  use  of  the  synovial  fluid. 

E.  Cartilage. 

1.  Cut  thin  slices  of  cartilage  from  the  ends  of 

the  bones ;  what  are  the  characteristics  of 
cartilage  ? 

2.  Why  is  cartilage  placed  at  the  ends  of  bones 

where  motion  occurs? 

F.  Bones. 

1.  Describe  the  way  the  bones  fit  together  at  the 

joint. 

2.  Is  twisting  motion  possible  at  this  joint  ? 

G.  Periosteum. 

Stick  the  point  of  the  scalpel  into  the  surface 
of  the  bone  where  all  the  muscle  has  been  re- 
moved. Peel  off  some  pi  the  thin  membrane 
(periosteum). 

1.  What  are  the  characteristics  of  periosteum  ? 

2.  Where  do  you  find  periosteum  on  long  bones  ? 
H.  Make  a  list  of  all  the  structures  found  in  the  joint, 

giving  the  use  of  each. 


STUDY   OF    THE    JOUVTS   US'    THE   BODY.         11 


7.  Study  of  the  Joints  in  the  Body. 

A.  Ball-and-socket  joints. 

1.  Note  on  the  articulated  skeleton  wliat  bones 

form  the  joint  at  the  shoulder. 

2.  Point  out  the  bones  forming  the  hip-joint. 

3.  State    the    points    of    resemblance    between 

these  two  joints. 

4.  Mention  all  the  differences  in  the  structure  of 

these  two  joints  which  you  can  see. 

5.  MoYe   your  right   arm   and  right  leg  at  the 

same  time  from  a  vertical  position  in  an 
arc  toward  the  right ;  state  the  greatest 
range  of  motion  possible  at  the  shoulder- 
joint  and  at  the  hip-joint. 

6.  In  the  same  way  move  the  arm  and  leg  in  an 

arc  forward  as  far  as  possible  ;  backward 
as  far  as  possible.  Compare  the  range  of 
motion  at  each  joint. 

7.  What  other  kinds  of  movements  are  possible 

at  these  joints  ? 

8.  Press    the    thumb    on    the    hip-bone   during 

these  movements,  then  on  the  edge  of  the 
shoulder-blade.  Is  either  of  the  two 
girdles  movable? 

B.  Hinge-joints. 

1.  Determine  from  the  articulated  skeleton  the 

bones  which  form  the  hinge-joint  at  the 
elbow. 

2.  What  bones  form  the  joint  at  the  knee  ? 

3.  What   projection    at   the    elbow   occupies   a 


12  LABORATORY   EXERCISES, 

position  corresponding  to  the  knee-cap  or 
patella  ? 

4.  Move  the  right  forearm  and  the  right  leg  at 

the  same  time ;  state  in  which  direction 
(i.e.,  anteriorly  or  posteriorly)  each  is  bent. 

5.  Is  lateral  motion  possible  at  either  joint  ? 

6.  Make  a  list  of  all  the  other  hinge-joints  in 

the  body,  naming  the  bones  which  form 
the  joint  in  each  case. 

C.  Pivot-joints. 

1.  Place  the  right  forearm  on  the  table  with  the 

palm  of  the  hand-upward.     Without  lifting 

the   elbow  from  the   table   turn   the   hand 

until  the  palm   of  the   hand  rests   on  the 

table. 

a.  Which  of  the  bones  of  the  forearm  has 

crossed  the  other  ? 
h.  Note   on    the  articulated    skeleton  what 

two    bones    form    this   pivot-joint    at 

the  elbow. 

2.  Study   the   two    top   vertebrae    of   the    spinal 

column  ;  move  the  vertebrae  on  each  other 
to  show  how  a  person  may  turn  his  head 
from  side  to  side. 

D.  Gliding  joints. 

1.  Count  on  the  ar^culated  skeleton  the  bones 

forming  the  wrist. 

2.  How  many  bones  form  the  ankle  ? 

3.  Which  bones  are  the  larger,  those  of  wrist  or 

ankle? 

4.  Move  your  right  wrist  and  right  ankle  in  the 

same  direction  at  the  same  time.     At  which 


EXPERIMENTS    WITH  JOINT   APPARATUS.       13 

joint  is  the  greater  range  of  movement 
possible  ? 

5.  Move  your  lower  jaw  in  as  many  directions 

as  you  can. 

a.  At  what  joint  does  this  movement  take 

place  ? 
h.  To  which  class  does  this  joint  belong  ? 

6.  Study  the  joints  between  the  vertebrae ;  move 

the  vertebrae  on  each  other  to  show  how 
one  may  bend  the  back  or  twist  the  spinal 
column. 


8.  Experiments  with  Joint  Apparatus. 

Note. — This  apparatus  was  devised  by  Dr.  G.  W.  Fitz  of  Harvard 
University.  The  experiment  is  adapted  from  '  *  Outline  of  Require- 
ments "  for  Harvard. 

A.  Action  of  biceps  muscle. 

1.  Fasten  at  hole  No.  3  the  lower  end  of  the  chain 

attached  to  balance  No.  1,  and  suspend  this 
balance  from  the  wire  w^hich  slides  on  the 
upright  rod.  This  balance  represents 
amount  of  force  exerted  by  the  biceps 
muscle. 

2.  Fasten  at  hole  No.  5  balance  No.  3,  so  that  it 

hangs  below  the  square  tube.  This  balance 
shows  the  weight  in  palm  of  the  hand  lifted 
by  the  biceps  muscle. 

3.  Balance  No.  2,  attached  to  upright  rod  and 

sleeve,  shows  amount  of  pressure  in  joint. 

4.  Pull  up  the  sliding  wire  on  the  upright  rod. 


14  LABORATORY   EXERCISES. 

5.  Pull  on  balance  No.  3  until  tlie  square  tube  is 

at  right  angles  to  the  upright  rod,  i.e.,  the 
forearm  is  horizontal. 

6.  Read  the  pressure  in  pounds  and  fractions  of 

pounds  on  each  balance,  and  record  them  in 
the  table  given  below. 

7.  Fix  the  sliding  wire  in  other  positions  on  the 

upright  rod,  and  get  other  sets  of  figures. 

8.  Record  all  j^our  results  in  a  table  as  follows  : 


Balance  No.  1. 


Balance  No.  2. 


Balance  No.  3. 


9.  What  relation  do  you  find  to  exist  between 
the  force  exerted  by  the  biceps  (balance 
No.  1)  and  the  sum  of  the  forces  exerted  at 
the  joint  (balance  No.  2)  and  on  the  palm  of 
the  hand  (balance  No.  3)  ? 
10.  Determine  from  a  study  of  your  results  above 
how  much  force  must  be  exerted  by  the 
biceps  muscle  in  order  to  lift  10  pounds  in 
the  palm  of  the  hand.  How  much  force 
must  be  exerted  to  lift  25  pounds  ? 
B.  Action  of  triceps  muscle. 

1.  Fasten  at   hoTe   No.  2  the  lower  end  of  the 

chain  attached  to  balance  No.  1,  and  sus- 
pend this  balance  from  the  wire  which  slides 
on  the  upright  rod.  This  balance  repre- 
sents the  amount  of  force  exerted  by  the 
triceps  muscle. 

2.  Fasten  at  hole  No.  5  balance  No.  3,  so  that  it 


EXPERIMENTS    WITH  JOINT   APPARATUS.       15 

may  be  used  to  pull  up  the  square  tube. 
This  balance  shows  the  weight  in  palm  of 
hand  moved  by  triceps  muscle. 

3.  Balance  No.  2,  attached  to    upright  rod  and 

sleeve,  shows  amount  of  pressure  in  joint. 

4.  Pull  up  the  sliding  wire  on  the  upright  rod. 

5.  Pull  up  on  balance  No.  3,  until  the  square  rod 

is  at  right  angles  with  the  upright  rod,  i.e., 
the  forearm  is  horizontal. 

6.  Fill  in  several  sets  of  figures  in  the  following 

table  by  experimenting  in  a  manner  similar 
to  that  suggested  in  A,  6,  7  above  : 


Balance  No.  1. 


Balance  No.  2. 


Balance  No.  3. 


7.  "What  relation  do  you  find  to  exist  between 
the  force  at  the  joint  (balance  No.  2),  and 
the  sum  of  the  forces  exerted  by  the  triceps 
(balance  No.  1)  and  at  the  palm  df  the 
hand  (balance  No.  3)  ? 
C.  Action  of  the  calf-muscles. 

1.  Fasten  at  hole  No.  1  the  lower  end  of  the 

chain  attached  to  balance  No.  1,  and  sus- 
pend this  balance  from  the  wire  which  slides 
on  the  upright  rod.  This  balance  shows  the 
amount  of  force  exerted  by  the  muscles  in 
the  calf  of  the  leg  which  pull  on  the  tendon 
of  Achilles. 

2.  Fasten   at  hole  No.  4,  by  means  of  the  pin, 

balance  No.  3,  so  that  it  may  be  used  to  pull 


16  LABOBATOUY  EXERCISES. 

up  the  square  tube.  This  balance  shows 
the  pressure  exerted  on  the  floor  bj  the  ball 
of  the  foot. 

3.  Balance  No.  2,  attached  to  the  upright  rod 

and  sleeve,  shows  amount  of  pressure  on 
ankle-joint  exerted  by  weight  of  body. 

4.  Experiment  with  this  arrangement  of  the  lever 

apparatus  until  you  obtain  several  sets  of 
figures.     (See  directions  A,  4,  5,  6,  7  above.) 
5.  Kecord  all  your  results  in  a  table  as  follows : 


Balance  No.  1. 


Balance  No.  2. 


Balance  No.  3. 


6.  From  a  study  of  your  results  above  compute 
the  following  : 

When  a  person  weighing  150  pounds  stands 
on  one  foot  with  the  weight  on  the  ball  of 
the  foot — 

a.  What   pressure    is   exerted   on    the 

floor? 
5.  What  force  is  pulling  on  the  tendon 
of  Achilles  in  order  to  produce  the 
al)ove  position  ? 
c.  What  is  the  pressure  on   the  ankle- 
joint  ? 
Answer  the  same  questions  when  the  per- 
son weighs  100  pounds. 


ACID    AND    ALKALINE   REACTIONS.  17 


9.  Acid  and  Alkaline  Reactions. 

Materials  :  Diluted  hydrochloric  acid,  dilute  caustic  soda  solution  ; 
red  and  blue  litmus  paper;   evaporating-dish,  alcohol-lamp. 

A.  Tests  for  acids  and  alkalis. 

1.  Place  a  drop  of  very  dilute  hydrochloric  acid 

on  blue  litmus  paper.     Result? 

2.  Place  a  drop  of  very  dilute  caustic  soda  solu- 

tion on  red  litmus  paper.     Besult  ? 

3.  Place  a  drop  of  the  hydrochloric  acid  on  the 

tongue.     What  is  the  taste? 

4.  In  the  same  way  determine  the  taste  of  the 

soda  solution. 

B.  Neutralization. 

1.  Pour  a  small  amount  of  the  hydrochloric  acid 

into  an  evaporating-dish  ;  add  caustic  soda, 
drop  by  drop,  until  pieces  of  red  and  blue 
litmus  paper  remain  unchanged  when 
dipped  into  the  liquid.  This  process  is 
called  neutralization. 

2.  Evaporate  the   liquid  in  the  dish  to  dryness 

over  an  alcohol-  or  gas-flame. 

a.  What  is  the  appearance  of  the  substance 

which  is  left  ? 

b.  What  is  its  taste  ? 

C.  Definitions.     From  the  above  experiments — 

1.  Give  some  characteristics  of  an  acid. 

2.  Give  some  characteristics  of  an  alkali. 

3.  Define  neutralization. 

D.  Applications. 

1.  Test  with  litmus   paper   the   following   sub- 


18 


LABORATORY  EXERCISES. 


stances  dissolved    in  water  :    soap,  lemon- 
juice,  ammonia,  cream  of  tartar,  saliva,  bak- 
ing-soda, apple-juice,  sugar,  white  of  egg. 
2.  Arrange  all  the  substances  you  have  tested  in 
a  table  like  the  following : 


Acid. 


Alkali. 


Neutral. 


10.  To  Determine  the  Amount  of  Water  in  Foods. 

Materials  :  Piece  of  lean  beef -steak  ;  two  potatoes  ;  weighing  bal- 
ances. 

A.  Percentage  of  water  in  beef-steak. 

1.  Weigh  the  piece  of  meat  and  put  it  aside  in  a 

warm  dry  place  ;  weigh  the'  next  day. 
Continue  the  weighings  each  day  until  the 
figure  remains  constant.  (The  loss  is 
mostly  water.) 

2.  Record  your  results  in  tabular  form  as  fol- 

lows : 

f 


First  day.. 

Second  day 

Third  day. 

etc 


Wt.  of  steak. 


Loss  of  original  wt. 


Per  cent,  of  loss. 


B.  Percentage  of  water  in  potatoes. 

1.  Remove  a  thin   layer  of  peel  from  one  of  the 
potatoes  ;  weigh  each  of  them  and  lay  aside 


TO    TEST   FOODS   FOR    STARCH.  19 

in  a  warm  dry  place.    Weigh  each  day,  and 
record  results    for   each    potato  in  tabular 
form  as  above. 
2.  What  is  one  use  of  the  peel  of  potato*^ 

11.  To  Test  Foods  for  Starch.* 

Maierials  :  Corn-starch,  grape-sugar,  wliite  of  Qgg,  mutton  tallow, 
water;  iodine  solution  ;  test-tubes,  glass  jar,  alcoliol-lamp. 

A.  Method  of  applying  iodine  test. 

Put  a   small  amount  of  corn-starch  in  a  test- 
tube,  add  water  and  shake  the  mixture. 

1.  Does  the  starch  dissolve  ? 

2.  Boil  the  mixture. 

a.   What  change  do  you  notice  ? 

h.  Has  the  starch  dissolved  ?  (Place  some 
sugar  and  water  in  another  test-tube, 
boil,  and  compare  with  the  boiled 
starch.) 

3.  Pour  a  little  of  the  starch  paste  into  a  test- 

tube,  add  a  drop  of  iodine,  and  record  re- 
sult. 

4.  Add  a  few  drops  of  the  starch  mixture  to  a 

large  glassful  of  water ;  stir  in  a  few  drops 
of  iodine.     What  is  the  result  ? 

5.  Pour  a  small  amount  of  iodine  into  a  test-tube 

of  water.     What  do  you  observe  ? 

6.  Put  a  small  amount  of  grape-sugar  into  a  test- 

tube  ;  into  a  second  test-tube  some  white  of 
egg  mixed  with  water  ;  and  into  a  third  tube 
put  some  mutton  tallow  (fat).  Add  a  little 
iodine  to  each. 


20  LABORATOBT  EXERCISES. 

a.  Do   you  notice   any  change  in  the  color 

of  any  of  the  substances  ? 
h.  Do  any  of  the  colors  resemble    at   all 
the   change    of    color  resulting    from 
the  addition  of  iodine  to  starch  ? 
7.  From  the   preceding  experiments  state  how 
you   may   determine   whether   a  substance 
contains  much    starch,  little  starch,  or  no 
starch. 
B.  Application  of  iodine  test  to  various  foods. 

1.  Test  as  many  foods  as  you  can  by  adding  hot 

water  to  each  on  a  porcelain  dish  and  then 
applying  iodine  (e.g.,  oatmeal,  flour,  meat, 
egg,  milk,  parsnip,  potato,  onions,  apples 
(both  green  and  ripe),  beans,  rice,  pepper). 

2.  Tabulate  your  results  in  columns  under  the 

following  heads : 


Much  starch. 


Little  starch. 


No  starch. 


12.  To  Test  Foods  for  Grape-sugar.* 

Materials  :  Grape-sugar,  corn-starch,  white  of  egg,  mutton  tallow, 
raisins,  onions,  grapes,  granulated  sugar,  and  other  foods;  Fehling's 
solution  ;  test-tubes,  alcohol-lamp. 

A.  Method  of  applying  Fehling's  test. 

1.  Dissolve  a   small  amount  of  grape-sugar  (glu- 
cose) in  water  in  a  test-tube. 
a.  What  is  the  taste  of  the  solution  ? 


TO    TEST   FOODS   FOB    GRAPE-SUGAR.  21 

h.  Add  some  Fehling's  solution  and  boil. 
What  changes  do  you  notice  ? 

2.  Into    the  first  of  three   test-tubes  put   some 

white  of  egg  mixed  with  water ;  into  a  sec- 
ond tube  some  corn-starch  ;  and  into  a  third 
tube  some  mutton  tallow  (fat).     Add  Fehl- 
ing's  solution  to  each  and  boil, 
a.  Does    any    change   take   place   in    the 

color  of  the  Fehling's  solution  ? 
h.  Do  any  of  the    colors    resemble    at   all 
the  color  of    the  Fehling's    solution 
when  it  was  boiled  with  grape-sugar  ? 

3.  How  can  you  determine  whether  or  not  grape- 

sugar  is  present  in  a  given  food  ? 
B.  Application  of  Fehling's  solution  test  to  various 
foods. 

1.  Test  as  many  different  kinds  of  foods  as  you 

can,  first  treating  them  with  water,  boiling 
in  a  test-tube  and  then  boiling  with  Fehl- 
ing's solution  (e.g.,  onions,  grapes  both  ripe 
and  unripe,  pears,  granulated  sugar,  honey, 
molasses,  meat,  egg). 

2.  Tabulate  your  results  in  columns  under  the 

following  heads : 


Grape-sugar  present. 


Grape-sugar  absent. 


22  LABORATORY  EXERCI8E8. 


13.  To  Test  Foods  for  Nitrogenous  Substances. 

Materials  :  White  of  &gg,  corn-starcli,  grape-sugar,  mutton  tallow, 
piece  of  meat,  milk,  peas  ;  concentrated  nitric  acid  and  ammonia  ;  test- 
tubes,  beaker-glass,  thermometer,  alcohol-lamp. 

A.  Effect  of  heat. 

1.  Pour  a  small  amount  of  the  white  of  an  egg 

into  a  test-tube.  (White  of  egg  is  composed 
of  nitrogenous  substances.)  Place  a  chem- 
ical thermometer  in  the  test-tube,  and  hold 
the  tube  in  a  beaker-glass  of  cool  water. 
Gradually  heat  the  water,  stirring^ contin- 
ually with  the  test-tube. 
a.  What  change  takes  place    in    the    egg 

albumen  ? 
h.  At  what  temperature   does  this  change 

occur  ? 

2.  In  the  same  way  try  the  effect  of  heat  on  milk 

(heating  several  times);  on  meat.     E-ecord 
results. 

B.  Smell  when  burning. 

1.  Place  a  small  piece  of  lean  meat  on  the  top 

of  a   coal  fire  and  allow  it  to  burn.  Have 

you  ever  noticed  this  smell  before  ?  If  so, 
what  caused  it  ? 

2.  In  the  same  way  test  milk,  peas,  or  beans. 

Eesult  ? 

C.  Effect  of  nitric  acid  and  ammonia. 

1.  Pour  a  little   concentrated   nitric   acid   on  a 
piece  of  hard-boiled  egg  in  a  test-tube. 
a.  What  do  you  observe  ? 


TO   TEST  FOODS  FOR  NITROGENOUS  SUBSTANCES.  23 

h.  Wash  off  tlie  egg  with  water,  add  a 
little  concentrated  ammonia,  and  note 
result. 

2.  Put  into  a  test-tube  some  starch  paste  made 

as  in  11  above  ;   into  a  second  tube   some 
grape-sugar ;    and    into    a   third     test-tube 
some  mutton  tallow  (fat).    Add  a  little  con- 
centrated nitric  acid  to  each  of  the  three. 
a.  Do   jou    observe     any    change    in    the 

color  of  either  of  these  nutrients  ? 
h.  Pour  off  the  acid  and  add  a  little    con- 
centrated ammonia.     Is  any  effect  no- 
ticeable ? 

3.  Test  with  a  drop  of  nitric  acid  the  skin  on  the 

tip  of  one  of  your  fingers. 
a.  What  is  the  result  ? 

h.  Of  what  material   is  the   human    body 
partly  composed? 

4.  Apply  the  nitric  acid  and  ammonia  test  to  as 

many  foods   as  you  can  (e.g.,  gelatin,  peas, 
white  meats,  onions,  fruits). 

5.  Tabulate  your  results  in  columns  under  the 

following  heads : 


Nitrogenous  substances  present. 


Nitrogenous  substances  absent. 


D.  From  the  above  experiments  state  briefly  three 
ways  of  testing  foods  for  nitrogenous  sub- 
stances. 


24  LABORATORY  EXERCISES. 


14.  To  Test  Foods  for  Fats  and  Oils. 

Materials  :  Grround  flaxseed,  corn-meai,  milk,  egg  ;  ether  or  ben- 
zine ;  beaker-glass. 

Caution  /  Never  handle  benzine  or  ether  near  a  flame  or  a  hot 
stove,  since  the  vapor  of  these  substances  is  very  inflammable. 

A.  Method  of  extracting  oils. 

To  two  or  three  teaspoonfuls  of  the  ground 
flaxseed  add  an  equal  volume  of  ether  or  ben- 
zine ;  stir  the  mixture  and  let  it  stand  for  ten  or 
fifteen  minutes.  Filter  and  place  the  liquid 
aside  in  a  good  draught  of  air  until  the  odor  of 
ether  or  benzine  has  disappeared. 

1.  What  kind  of  substance  have  you  obtained  ? 

2.  What  is  its  smell? 

3.  Why  is  benzine  used  to  remove  grease-spots 

from  clothing  ? 

B.  In  the  same  way  extract  the  fats  from  milk  ;  from 

egg. 

C.  Kub  a  little  of  the  flaxseed  on  paper.     What  effect 

does  it  have  on  the  paper?     (This   is   a  simple 
way  of  proving  the  presence  of  fats.) 

15.  To  Test  Foods  for  Mineral  Substances.* 

Materials:  Piece  of  meat,  oatmeal,  egg,  milk  ;  spoon  or  piece  of 
metal. 

A.  Method  of  testing  for  mineral  matter. 

Place  a  piece  of  dried  meat  on  a  spoon  or  on  a 
shovel,  and  let  it  burn  on  a  hot  coal  fire  or  over  a 
gas-flame  until  no  other  change  can  be  brought 
about  by  heat. 


TEE   ANALYSIS    OF   FLOUR.  25 

1.  What   is   the    appearance    of   the    substance 

which  is  left  behind?    (The  ash  is  the  min- 
eral substance.) 

2.  What  is  the  effect  of  heat  on  this   substance  ? 
B.  In  the  same  way  test  oatmeal,  egg,  and  milk.    What 

do  jou  learn  in  regard  to  the  presence  of  mineral 
substances  in  these  foods  ? 


16.    The  Analysis  of  Flouh.* 

Materials  :  Flour,  water ;  concentrated  nitric  acid  and  ammonia, 
iodine,  Feliling's  solution  ;  cotton  clotli,  test-tubes,  glass  disli,  piece 
of  metal. 

Moisten  some  flour  with  water  until  it  forms  a  tough, 
tenacious  dough ;  tie  it  in  a  piece  of  cotton  cloth,  and 
knead  it  in  a  vessel  containing  water.  Set  aside  the 
dish  with  the  water. 

A.  Gluten. 

1.  What  are  some  of  the  characteristics  of  the 

substance  (principally  gluten)  within  the 
cloth  ?     Draw  it  out  into  threads. 

2.  Test  it  with  nitric  acid  and  ammonia.     What 

kind  of  nutrient  is  gluten  ? 

B.  Carbohydrates. 

1.  Test  with  iodine  a  small  amount  of  the  sedi- 

ment in  the  water  which  you  used  at  the 
beginning  of  the  experiment.  What  part  of 
the  flour  was  washed  through  the  cloth  ? 

2.  Test  with  nitric  acid  and  ammonia  another 

portion.  Are  nitrogenous  substances  pres- 
ent? 


26  LABOBATORT  EXERCISES. 

3.  Test  a  small  portion  of  the  sticky  mass  in  the 

cloth  with  iodine.     What  is  the  result,  and 
what  is  jour  conclusion  ? 

4.  Place  a  little  flour  in  a  test-tube,  add  water 

and  boil ;  add  Fehling's  solution  and  boil 
again.     Is  grape-sugar  present  in  flour  ? 

C.  Mineral  matter.  i 

Place  a  small  amount  of  dry  flour  on  a  piece 
of  tin  or  other  metal  and  cause  it  to  burn  over 
a  flame. 

1.  What  changes  take  place  ? 

2.  What  is  left  after  the  burning  ? 

D.  Summary. 

1.  What  nutrients  are  present  in  flour  ? 

2.  State  how  each  of   these  nutrients  may  be 

separated  from  the  rest. 


17.    The  Study  of  Milk.* 

Materials :  Pint  of  fresh,  rich  milk  ;  nitric  acid  and  ammonia, 
Fehling's  solution,  iodine,  caustic  soda,  osmic  acid,  vinegar  ;  test- 
tubes,  lactometer,  cloth,  piece  of  metal,  alcohol-lamp. 

A.  Fats. 

Put  the  milk  into  a  clean  glass  dish,  and  allow 
it  to  stand  over  night. 

1.  What  layers  can  be  distinguished  ? 

2.  Remove  by  means  of  a  spoon  the  top  layer 

into  a  bottle  or  cup  (No.  1). 

3.  Place  a  drop  of  it  on  unglazed  paper.     Let 

the  paper  dry  for  some  time.     What  kind 
of  nutrient  is  shown  to  be  present  in  milk  ? 


THE   STUDY   OF  MILK.  27 

B.  Nitrogenous  substances. 

1.  Boil  the  rest  of  tlie  milk  ;  what  change  is  no- 

ticed ?  What  kind  of  nutrient  is  affected  in 
this  way  by  heat  ? 

2.  Remove  the  scum  from  the  milk  and  place  it 

in  a  second  cup  (No.  2).  Test  a  little  of  it 
with  nitric  acid  and  ammonia.     Result  ? 

3.  Add  vinegar  to  the  rest  of  the  milk  and  strain 

through  a  cloth.  What  kind  of  substance 
is  left  in  the  cloth?  Test  it  with  nitric 
acid  and  ammonia.  Result?  Place  this 
substance  in  cup  No.  2. 

C.  Carbohydrates. 

1.  Test  a  small  amount  of  fresh  milk  with  Feh- 

ling's  solution.  Result  ?  (Milk-sugar  or 
lactose  sometimes  gives  the  test  with  Feh- 
ling's  solution  like  grape-sugar.) 

2.  Test  milk  with  iodine.     Is  starch  present  ? 

D.  Specific  gravity  of  milk.     (In  class.) 

1.  Pour  some  good  rich  milk  into  a  tall  glass  jar. 

Test  it  with  a  lactometer  and  record  specific 
gravity. 

2.  Set  the  milk  aside  to  allow  the  cream  to  rise. 

Remove  the  cream  and  test  the  skim-milk 

with  the  lactometer. 

a.  What  change  in  specific  gravity  do  you 

note? 
h.  Explain  this  change. 

3.  Determine  the  specific  gravity  of  a  second  por- 

tion of  milk.  Dilute  the  milk  with  water 
and  again  find  specific  gravity.  (Fresh  un- 
skimmed milk  usually  has  a  specific  gravity 


^*t(tti- 


28  LABORATOUT  EXERCISES. 

of  1028  to  1034.)  How  can  adulteration  of 
milk  be  detected  ? 

E.  Microscopic  examination  of  milk.     (In  class.) 

1.  Place  a  drop  of   milk  on  a  clean  glass  slide, 

and    cover   with    a    cover-glass.     Examine 

under  the  compound  microscope. 

a.  What  is  the  appearance  of  the  oil- 
globules  ? 

h.  Are  they  all  of  the  same  size  ?  (The  fat 
in  milk  is  said  to  be  in  a  state  of 
emulsion.) 

2.  Place  a   drop   of  dilute  caustic   soda  at  the 

edge  of  the  cover-glass.  What  is  the  effect 
of  the  soda  on  the  oil-globules  ? 

3.  Prepare  a  second  drop  of  milk  for  examina- 

tion as  directed  above  (1).  Place  a  drop  of 
osmic  acid  solution  at  the  edge  of  the  cover- 
glass.  What  is  the  effect  of  the  osmic  acid 
on  the  oil -globules? 

F.  Reaction  of  milk  when  tested  with  litmus. 

1.  Test  some  fresh  milk  with  red  and  blue  litmus 

paper.     Is  it  acid,  alkaline,  or  neutral  ? 

2.  Set  the  milk  aside  in  a  warm  place  and  allow 

it  to  sour.  Again  test  it  with  the  red  and 
blue  litmus  paper.  What  is  its  reaction 
now  ?  (The  souring  of  milk  is  caused  by 
the  action  of  certain  micro-organisms  called 
bacteria.     See  study  of  bacteria,  44.) 


THE    STUDY   OF    THE   MOUTH.  29 


18.  The  Stitdy  of  the  Mouth.* 

Take  a  position  with  your  back  toward  a  strong 
light  and  stndj  your  mouth-cavity  by  means  of  a 
hand-mirror. 

A.  Walls  of  the  mouth-cavity. 

1.  Press  the  forefinger  against  the  upper,  lower, 

and  side  walls  of  the  mouth ;  in  which  of 
these  regions  are  the  walls  rigid  (bone)  ?  in 
which  regions  are  they  yielding  (muscle)  ? 

2.  "What  differences    do  you  note  between   the 

outer  and  inner  coverings  of  the  cheek  ? 
What  are  the  characteristics  of  mucous 
membrane  (inner  covering)  ? 

3.  Pull  aside  with  the  forefinger  one  corner  of 

the  mouth.  Notice  the  small  elevation  on 
the  inside  of  the  cheek.  Opposite  what 
tooth  does  it  lie  ?  (The  duct  from  one  of 
the  salivary  glands  opens  on  this  elevation.) 

4.  Press  the  tongue  down  with   the  forefinger. 

Describe,  with  figure,  the  opening  into  the 
throat  or  pharynx. 

5.  If  possible,  locate  and  describe  the  tonsils. 

B.  The  teeth. 

1.  Close  the  jaws    and   open   the  lips ;  do   the 

front  teeth  of  the  upper  jaw  cover  the  ends 
of  the  lower  teeth  or  vice  versa  ? 

2.  Are  the  front  teeth  of  the  upper  jaw  larger 

or  smaller  than  those  of  the  lower  jaw  ? 

3.  Count  your  teeth  and  record  result  in  a  table 

like  the  following : 


30 


LABORATORY  EXERCISES, 


Incisors. , .  . 
Canines . . . . 
Bicuspids. . . 
Molar 


Right  half  of 
upper  jaw. 


Left  half  of 
upper  jaw. 


Right  half  of 
lower  jaw. 


Left  half  of 
lower  jaw. 


4.  Place  a  piece  of  string  between  the  teetli  and 
describe  motion  of  jaws  in  biting  it  oft*. 
Describe  the  movements  of  the  jaws  in 
chewing. 

C.  The  tongue. 

1.  What  is  the  shape  of  the  tongue  ? 

2.  Where  is  the  tongue  attached  ?  ^ 

3.  What  parts  of  the  walls  of  the  mouth-cavity 

can  be  touched  by  the  tip  of  the  tongue  ? 

4.  What   differences   do  you  note  between  the 

upper  and  lower  surfaces  of  the  tongue  ? 

D.  The  use  of  the  lips  and  tongue  in  speaking. 

1.  Pronounce  the  vowels  of  the  alphabet : 
^    a.  Are  the  lips  closed  or  open  ? 

h.  Does  the  tip  of  the    tongue    touch   the 
teeth  ? 

c.  Does  the  tip    of   the  tongue  touch  the 

palate  ? 

d.  How  is   the  shape  of  the  mouth-cavity 

altered    to    pronounce    these   different 
letters  ? 

2.  What  consonants  necessitate  the  closing  of  the 

lips  ?  (These  consonants  are  called  labials.) 

3.  What  consonants  require  the  tongue  to  touch 

the  teeth  or  the  palate  ?     (These  are  called 
the  lingual  consonants.) 


L 


TO    PREPAEE   DIGESTIVE  JUICES.  31 


19.  To  Prepare  Digestive  Juices,  f 

Materials:  Cardiac  end  of  pig's  stomach  ;  pancreas  of  pig  ;  gall  of 
ox  ;  strong  glycerin,  .2%  solution  of  liydro chloric  acid,  1.5^  solution 
of  sodium  carbonate  ;  solid  pepsin,  pancreatin,  and  ox-gall. 

A.  Preparation  of  pepsin  solution. 

Procure  the  stomach  of  a  pig,  wash  it  out  with 
a  gentle  stream  of  water.  Tear  oft  the  mucous 
membrane  from  j;he  cardiac  (oesophageal)  end  of 
the  stomach.  Dry  the  membrane  between  folds 
of  blotting-paper,  and  mince  it  finely.  Place  in  a 
bottle  and  add  5  times  its  bulk  of  strong  glycerin. 
Set  aside  for  several  days,  stirring  occasionally. 
Filter  through  muslin.  (The  glycerin  dissolves 
the  pepsin.)  The  glycerin  extract  may  be  kept 
almost  indefinitely. 

When  required  for  use  in  digesting  nitrogenous 
substances,  add  10  times  its  volume  of  .2%  hydro- 
chloric acid,  and  filter. 

Instead  of  preparing  the  glycerin  extract  an 
artificial  gastric  juice  may  be  made  by  dissolving 
solid  pepsin  in  water  and  adding  the  hydrochloric 
acid. 

B.  Preparation  of  pancreatin  solution. 

Leave  the  pancreas  of  a  pig  moistened  with 
water  for  a  day  ;  then  mince  it  well  and  add  10 
times  its  volume  of  strong  glycerin.  Set  the 
mixture  aside  for  several  days,  stirring  occasion- 
ally. Filter  through  muslin.  (The  glycerin  dis- 
solves out  the  pancreatin.) 

The  glycerin  extract  acts  on  starch  and  nitro- 
genous   substances.     When   required    to   digest 


32  LABORATORY  EXERCISES. 

fats  add  10  volumes  of  1.5^  solution  of  sodium 
carbonate,  shake  and  filter. 

An  artificial  pancreatic  juice  may  be  made  by 
dissolving  solid  pancreatin  in  water  and  adding 
the  sodium  carbonate  solution. 
C.  Preparation  of  bile. 

Procure  the  fresh  gall-bladder  of  an  ox ;  wash 
it,  make  a  small  opening  with  a  knife,  and  collect 
the  bile  in  a  bottle.  (The  bile  of  herbivorous 
animals  is  green  in  color ;  liuman  bile  when  fresh 
is  a  golden-brown  liquid.) 

A  solution  of  solid  ox-gall  in  water  may  be 
used  instead  of  the  contents  of  the  gall-bladder, 
if  the  latter  cannot  be  easily  obtained. 


20.   The  Digestion  of  Starch. 

MateriqJ^s  :  Corn-starch,    pancreatin   solution,    saliva ;  test-tubes  ; 
alcobol-lamp. 

A.  By  saliva. 

Put  a  small  amount  of  corn-starch  in  a  test- 
tube,  add  water  and  boil ;  dilute  the  paste  until  a 
smooth,  thin  mixture  is  formed. 

1.  Pour  into  a  test-tube  a  small  amount  of  this 

starch  mixture,  and  test  with  Fehling's 
solution.  What  is  the  result  and  what  is 
your  conclusion? 

2.  Allow  some  saliva  to  flow  from  the  mouth  into 

a  clean  test-tube;"^  test  it  with  Fehling's 
solution.     What  is  your  inference  ? 

♦Saliva  sufficient  for  tlie  class  may  be  obtained  by  the  teacher 
before  the  exercise. 


TEE   DIGESTION    OF  MINERAL    SUBSTANCES.     33 

3.  Pour  some  saliva  into  the  starch  paste  made 

at  the  beginning  of  the  experiment,  shake 
the  mixture  and  warm  gently  for  a  moment 
or  two.  Test  with  Fehling's  solution. 
Kesult  ? 

4.  What  is  the  effect  of  saliva  on  boiled  starch  ? 

5.  Name    several    foods  already  studied   which 

might  be  partially  digested  by  saliva. 

6.  Hold   a   small   amount  of   the    boiled  dilute 

starch  paste  in  the  mouth.  What  is  the 
taste  at  first  ?  Do  you  notice  any  change ; 
if  so,  what  change  ? 

B.  By  pancreatic  juice. 

1.  Dissolve  a   little  pancreatin  in  water.     Test 

a  small  portion  of  it  with  Fehling's  solu- 
tion.    What  is  your  conclusion  ? 

2.  Add  some  pancreatin  solution  to  some  of  the 

starch  paste  ;  warm  and  test  with  Fehling's 
solution.     Besult  ? 

C.  What  digestive  juices  of  the  human  body  act  upon 

starch  ? 


21.  The  Digestion  of  Mineral  Substances. 

Materials :   Table-salt,    phosphate    of    lime,  diluted  hydrochloric 
acid  ;  evaporating-dish,  alcohol- lamp. 

A.  Soluble  salts. 

Put  some  table-salt  into  a  test-tube,  add  water, 
and  shake  well. 

1.  Does  the  salt  dissolve?     How  do  you  know? 

2.  In  what  part  of  the  alimentary  canal  may  salt 

become  liquefied,  and  how  ? 


34  LABORATORY   EXERCISES, 

3.  What  is  meant  by  a  soluble  salt  or  soluble 
mineral  substance  ? 
B.  Insoluble  salts.  v_y 

Put  some  phosphate  of  lime  (one  of  the  con- 
stituents of  milk)  into  a  test-tube,  add  water,  and 
shake  well. 

1.  Does  the  substance  dissolve  ?     How  do  you 

know? 

2.  Add   a  little  diluted   hydrochloric  acid  and 

shake.     What  change  do  you  observe  ? 

3.  Evaporate  to  dryness  in  an  evaporating-dish 

some  of  the  liquid  obtained  in  2. 

a.  What  is  the  appearance  of  the  substance 

which  is  left  ? 

b.  Will  it  dissolve  in  water  ? 

c.  Into  what  kind  of  a  salt  has  hydrochloric 

acid  changed  the  insoluble  salt  ? 

22.  The  Digestion  of  Nitrogenous  Substances. 

Materials:  Hard-boiled  egg  ;  pepsin  and  pancreatin  solutions,  liy- 
drocliloric  acid,  bicarbonate  of  soda  ;  test-tubes. 

A.  Test  No.  1 

Thoroughly  mince  a  piece  of  hard-boiled  egg, 
and  place  a  portion  of  it  in  a  test-tube  ;  half-fill 
the  tube  with  water ;  add  some  pepsin.  Label 
the  tube  "  No.   1,  Minced  egg  -|-  pepsin." 

B.  Test  No.  2. 

Place  in  another  test-tube  the  same  quantity 
of  minced  egg,  water,  and  pepsin  as  in  tube  No. 
1  ;  add  a  little  dilute  hydrochloric  acid.  Label 
"  No.  2,  Minced  egg  +  pepsin  +  hydrochloric 
acid." 


THE  BIOESTION    OF  NITROGENOUS   SUBSTANCES.  35 

C.  Test  No.  3. 

Put  a  lump  of  the  hard-boiled  egg  in  a  test- 
tube  ;  add  water,  pepsin,  and  hydrochloric 
acid  as  in  tube  No.  2.  Label  "  No.  3,  Lump  of 
e^g  -\-  pepsin  -|-  hydrochloric  acid." 

D.  Test  No.  4. 

Into  another  test-tube  put  some  of  the  minced 
egg ;  half-fill  the  tube  with  water  and  add  pan- 
creatin  ;  pour  in  a  few  drops  of  dilute  hydro- 
chloric acid.  Label  *'No.  4,  Minced  egg  -|-  pan- 
creatin  -|-  hydrochloric  acid." 

E.  Test  No.  5. 

In  a  fifth  test-tube  mix  the  same  quantity  of 
minced  egg,  water,  and  pancreatin  as  was  used  in 
No.  4 ;  add  to  the  mixture  a  little  baking-soda. 
Label  "No.  5,  Minced  egg  -\-  pancreatin  -(- 
baking-soda." 

Shake  all  five  mixtures  well  and  set  them 
aside  in  a  warm  place.  Examine  them  at  the 
end  of  the  first  few  hours,  at  the  end  of  24 
hours,  etc. 

F.  Results. 

1.  Compare  tubes  No.  1  and  No.  2. 

a.  In  which  tube  has  the  egg  been  lique- 
fied or  digested  ? 

h.  Is  the  acid  necessary  for  gastric  diges- 
tion ? 

2.  Compare  tubes  No.  2  and  No.  3. 

a.  In  which  tube  is  digestion  more  com- 
plete ? 

h.  What  do  you  learn  in  regard  to  the  ef- 
fect of  thorough  mastication  of  food  ? 


36  LABORATOBY  EXERCISES. 

3.  Compare  tubes  No.  4  and  No.  5. 

a.  In    which    tube    has    digestion    taken 

place  ? 
h.  Does  pancreatin  perform   its   digestive 

action  in  an  acid  or   in   an  alkaline 

medium  ? 


23.  The  Digestion  of  Fats. 

Materials:  Butter,  olive-oil,  lard,  white  of  egg  ;  sodium  carbonate, 
caustic  soda,  hydrochloric  acid  ;  bile,  pancreatin  ;  test-tubes,  ther- 
mometer, beaker-glass  of  water,  alcohol-lamp,  apparatus-stand  ;  com- 
pound microscope,  slide,  cover-glass. 

A.  Effect  of  heat  on  fats. 

1.  Put  a  small  piece  of  butter  in  a  test  tube ; 

hold  the  test-tube  and  the  thermometer  in 
a  beaker-glass  of  water,  and  heat  the  water. 

2.  At  what  temperature  does  the  butter  melt  ? 

3.  Does  this  change  take  place  below  the  tem- 

perature of  the  body  (98.5°  Fahrenheit)  i.e., 
will  butter  melt  in  the  mouth  ? 

B.  Emulsion  of  fats. 

1.  In  a  test-tube  shake  up  a  few  drops  of  olive- 
oil  with  some  caustic  soda  solution. 
a.  What  change  takes  place  in  the  appear- 
ance of  the   mixture   after   shaking? 
(This  mixture  is  called  an  emulsion.) 
h.  Put  a  drop  of  the   mixture  on  a  glass 
slide,  cover  with  a  cover-glass,  and  ex- 
amine with  a  compound  microscope, 
(1)  What  is  the  appearance  of  the  oil 
droplets  ? 


THE   BIOESTION    OF  FATS.  37 

(2)  Compare  this  appearance  with  that 
seen  in  milk. 

2.  In  a  test-tube    shake   some   olive-oil  with   a 

mixture    of    white    of    egg   (albumen)  and 
water. 

a.  What  is  the  appearance  of  the  mixture  ? 
h.  Examine  a  drop   under  the    compound 
microscope  as  directed  above. 

3.  Shake  up  a  few  drops  of  the  olive-oil  with 

water  in  a  third  test-tube. 

a.  Compare  the  mixture  of  oil  and  water 

with  the  mixtures  formed  in  1  and  2 
above. 

b.  What  differences  do  you  notice  in  the 

tubes  ? 

4.  Summary. 

a.  Define  an  emulsion. 

h.  State   two  ways  in  which   an  emulsion 
may  be  made. 
C.  Saponification  of  fats. 

1.  Put  a  little  lard  or  olive  oil  in  a  test-tube,  add 

caustic  soda,  and  boil. 

a.  What  is  the  appearance  of  the  mix- 
ture ? 

h.  Examine  a  drop  under  the  compound 
microscope  as  directed  above.  Do 
you  see  any  difference  between  this 
mixture  and  that  formed  in  B  1 
above  ? 

c.  Taste  of  the    mixture.     What    kind   of 

substance  has  been  formed  ? 

2.  What  is  meant  by  saponification  ? 


38  LABORATORY  EXERCISES. 

D.  Effect  of  acids  and  alkalis  on  fats. 

1.  Pour  a  little  melted  butter  into  each  of  two 

test-tubes.  Add  to  test-tube  No.  1  some 
diluted  hydrochloric  acid  ;  to  test-tube  No. 
2  some  sodium  carbonate  solution.  Shake 
both  tubes  well,  and  allow  them  to  stand 
for  a  few  moments. 

2.  Does  the  butter  remain  mixed  better  with  an 

acid  or  with  an  alkali  ? 

E.  The  di£2festive  action  of  bile. 

1.  Test  with  litmus  paper  the  bile  solution.     Is 

it  acid,  alkaline,  or  neutral  ? 

2.  Pour  a  little  melted  butter  into  a  test-tube ;  add 

some  of  the  bile  solution.  Does  the  mixture 
resemble  that  formed  in  B  1  or  B  3  above  ? 

3.  Examine   a  drop   of  the  mixture  under  the 

compound  microscope.     Does  this  observa- 
^  tion  agree  with  that  made  in  2  just  above  ? 

4.  Pour  a  little   thin   starch  paste  into  a  test- 

tube  ;  add  some  bile,  and  after  a  time  test 
the  mixture  with  Fehling's  solution.  Does 
the  bile  act  upon  starch  ? 

5.  Place    in  another  test-tube   a    little   minced 

white  of  egg ;  add  bile  and  set  aside  for  a 
.  day  or  two.     Does  the  egg  dissolve  ? 

6.  State  what  kinds  of  food-stuffs  are  acted  upon 

by  bile,  and  what  kinds  of  food-stuffs  are 
not  acted  upon. 

F.  The  digestive  action  of  pancreatic  juice. 

1.  Prepare  some  artificial  pancreatic  juice  as  di- 
rected in  19  B,  adding  the  sodium  carbon- 
ate solution  to  make  it  alkaline. 


THE  PRINCIPLES    OF    OSMOSIS.  39 

2.  Sliake  up  a  little  melted  butter  with  some  of 

this  pancreatic  juice.  What  kind  of  a  mix- 
ture is  formed?  Examine  under  the  com- 
pound microscope. 

3.  What  kind  of  food-stuffs  are  digested  by  the 

action  of  pancreatic  juice  (compare  pre- 
vious experiments),  and  what  kind  of  food- 
stuffs are  not  acted  upon  ? 


24.    The  Principles  of  Osmosis,  f 

Materials :  Tubes  of  animal  intestine,  thistle-tube,  beaker-glass, 
grape-sugar,  starch,  white  of  egg,  butter,  salt,  Fehling's  solution, 
iodine,  nitric  acid  and  ammonia. 

Procure  the  intestines  of  a  sheep.  Clean  and 
inflate  them ;  tie  at  intervals  of  8  inches,  and 
allow  this  animal  membrane  to  dry.  Cut  the  suc- 
cessive portions  of  the  intestines  in  such  a  way 
as  to  form  small  tubes  closed  at  one  end. 
A.  Experiments  to  determine  what  nutrients  Avill  pass 
through  an  animal  membrane. 

Suspend  by  a  piece  of  wire  in  a  beaker-glass 
of  water  one  of  the  test-tubes  made  by  cutting 
up  the  dried  intestines.  Carefully  pour  into  the 
tube  a.  solution  of  grape-sugar.  Allow  it  to  stand 
for  an  hour. 

1.  Test  the  water  on  the  outside  of  the  tube  with 

Fehling's  solution.     What  is  the  result? 

2.  Will    grape-sugar   pass   through    an    animal 

membrane  ? 

3.  Using  other  tubes  of  animal  membrane,  deter- 

mine  whether    starch,    white    of    egg   (al- 


40 


LABOBATOBX  EXERCISES. 


bumen),  butter,  or  salt  solution  will  pass 
out  into  the  water  outside  the  tube.     (See 
Experiments  10-14  above.) 
4.  Classify  all  the  substances  you  have  tested  in 
a  table  like  the  following  : 


Crystalloids. 

(Substances  wliicli  will  readily- 
pass  through  an  animal  mem- 
brane.) 


Colloids. 
(Substances  which  will  not  readi- 
ly   pass    through    an     animal 
membrane. ) 


B.  Experiments  to  illustrate  osmosis. 

Slit  open  one  of  the  tubes  made  from  the 
sheep's  intestine  and  cover  the  larger  end  of  a 
thistle-tube  with  a  piece  of  this  membrane,  ty- 
ing it  tightly.  Pour  into  the  smaller  end  of  the 
^thistle-tube  a  rather  thick  solution  of  grape- 
sugar,  half-filling  the  tube.  Stand  the  thistle- 
tube  (membrane  down)  in  a  glass  dish  filled  with 
water  up  to  the  level  of  the  grape-sugar  solution. 
Mark  this  point  on  the  glass  dish.  Connect  a 
long  piece  of  glass  tubing  to  the  smaller  end 
of  the  thistle-tube  and  support  it  in  a  vertical 
position.  Examine  the  apparatus  at  the  end  of 
several  hours. 

1.  Notice  the  level  now  reached  by  the  liquid 

within  the  thistle-tube.  What  change  has 
taken  place  since  the  experiment  was 
begun  ? 

2.  Measure  the  difference  between  the  level  of 

the  liquid  within  the  thistle-tube  and  the 
level  of  the  liquid  in  the  glass  dish. 


THE   PRINCIPLES    OF    OSMOSIS.  41 

3.  Test  the  water  on  the  outside  of  the  thistle- 

tube  (in  the  glass  dish)  with  Fehling's  solu- 
tion.    What  is  the  result  ? 

4.  How  do  you  account  for  this  result  ? 

5.  Which  of  the  two  liquids  (the  water  in  the 

glass  dish  or  the  grape-sugar  solution  in 
the  thistle-tube)  was  the  denser  at  the  be- 
ginning of  the  experiment? 

6.  Has  more  liquid  passed  into  the  thistle-tube 

or  out  from  it  ?     How  do  you  know  ? 

7.  When   two    liquids   of   different    density   are 

separated    by   an   animal    membrane   what 
change  takes  place  ? 

8.  Is   the  greater  flow  of  liquid  from  the  less 

dense  to  the  more  dense  or  vice  versa  ? 

9.  Mark  the  level  of  the  liquid  in  the  thistle-tube 

at  the  end  of  each  successive  24  hours. 
What  inferences  do  you  draw  ? 

Note. — Parcliment  paper  may  be  used  instead  of  the  dried  sheep's 
intestine  to  cover  the  end  of  the  thistle-tube.  Or  a  membrane  may 
be  obtained  which  will  answer  the  purpose  by  dissolving  the  mineral 
portion  of  an  egg-shell,  leaving  the  lining  membranes  intact ;  the 
membrane  may  then  be  tied  to  the  end  of  the  tube. 

C.  Application  of  the  experiments. 

1.  In  what  respects  does  the  experiment  with 

the  thistle-tube  illustrate  the  process  of 
absorption  from  the  alimentary  canal  ? 

2.  In  what  respects  does  the  experiment  fail  to 

illustrate  that  process  ? 


42 


LABOBATORT  EXERCISES. 


25.  Digestion  of  Nutkients.* 


Kind  of  nutrient. 


Water 

Soluble  salts 

Insoluble  salts.  . . . 
Starch 

Sugar 

Fats 

Nitrogenous  foods, 


Digested  in 


Digested  by 


Changed  to 


Absorbed  in 


26.  Composition  of  the  Blood.  • 

Materials  :  Concentrated  nitric  acid  and  ammonia,  iodine  solution, 
Febling's  solution  ;  test-tubes,  alcobol-lamp  ;  tbree  bottles  of  blood 
material  prepared  as  follows  :  Fill  bottle  No.  1  with  blood  of  the  ox, 
(at  slaughter- liouse),  set  it  aside  at  once  where  it  will  not  be  dis- 
turbed, and  leave  it  for  a  day  or  two,  labelled  "  Clotted  Blood." 
Collect  some  blood  in  a  pail  and  rapidly  whip  it  with  a  brush-broom 
or  some  twigs  for  several  minutes  ;  fill  bottle  No.  2  with  the  red 
liquid  remaining  in  the  pail,  labelling  it  "Defibrinated  Blood." 
Collect  the  stringy  substance  clinging  to  the  broom,  wash  it  with 
water  until  it  is  white,  and  place  it  in  bottle  No.  3  in  a  2^  solution  of 
formalin  or  in  80^  alcohol ;  label  it  "Blood-fibrin." 


A.  Study  of  clotted  blood. 

1.  What  is  tlie  shape,  size,  and  consistency  of 

the  blood-clot? 

2.  What  is  the  color  of  the  clot  ? 

3.  What  is  the  color  of  the  liquid  serum  ? 

4.  Pour  off  the  serum  into  another  bottle  of  the 

same   size ;    what  proportion   of  blood  ap- 
pears to  be  serum  ? 


COMPOSITION    OF    TEE   BLOOD.  43 

5.  What  change  in  the  clot  do  you  notice  after 
the  removal  of  the  serum  ? 

B.  Study  of  blood-serum, 

1.  Pour  a  small  portion  of  the  serum  into  a  test- 

tube  and  heat  gradually  over  an  alcohol- 
lamp  ;  what  change  takes  place  ?  What 
kind  of  food-stuff  do  you  conclude  to  be 
present  in  the  serum  ? 

2.  Test  the  serum  with  iodine ;  what  is  your  in- 

ference ? 

3.  Test  another  portion  of  the  serum  with  Feh- 

ling's  solution.     Ilesult? 

4.  Place  a  drop  of  the  serum  on  a  piece  of  paper ; 

how  is  the  paper  affected?  What  other 
food-stuff  do  you  therefore  conclude  to  be 
present  ? 
.  5.  Heat  a  small  amount  of  the  serum  in  a  spoon 
until  it  has  burned  ;  what  kind  of  substance 
is  left? 
6.  Name  all  the  kinds  of  food-stuffs  you  have 
found  present  in  blood-serum. 

C.  Study  of  blood-fibrin. 

1.  Remove  a  piece  of  fibrin  from  bottle  No.  3 ; 

pull  it  apart.  What  are  some  of  its  char- 
acteristics ? 

2.  Test  the  fibrin  with  nitric  acid  and  ammonia ; 
■    what  is  its  composition  ? 

D.  Study  of  defibrinated  blood. 

1.  What  ingredient  of  the  blood  is  wanting  in 

bottle  No.  2  ?     (See  directions  above.) 

2.  What  is  the  effect  on  coagulation  of  removing 

this  substance  from  blood  ? 


44  LABORATORY   EXERCISES. 


27.    Change  in  the  Blood  after  Mixing  with 

Oxygen,  t 

Materials :  Defibrinated  blood  used  in  26  ;  glass  bottle  aud  stopper. 

A.  Pour  a  small  quantity  of  defibrinated  blood  into  a 

glass  bottle.     Describe  its  color. 

B.  Stopper  the  bottle  tightly  and  shake  it  violently 

for  a  minute  or  two. 

1.  What  change  has  taken  place  in  the  appear- 

ance of  the  blood  ? 

2.  What  caused  this  change  ? 


28.    Microscopic  Study  of  Corpuscles,  f 

Materials  :   Prepared  slides  of  frog's  blood  and  of  human  blood; 
compound  microscope  (500  diameters). 

A.  Corpuscles  of  frog's  blood. 

1.  How  many  distinct  types  of  solid  bodies  (cor- 

puscles) can  you  see  in  the  frog's  blood  ? 

2.  Is  there  any  variation  in  the  form  or  size  of 

different  corpuscles  of  the  same  type  ? 

3.  Draw  two    corpuscles  (differing  as    much  as 

possible)  of  each  type,  much  enlarged,  label- 
ling nucleus  and  cell-body. 

B.  Corpuscles  of  human  blood. 

1.  What  is  the  form  of  the  corpuscles  in  human 

blood  ?    (Examine  several  corpuscles  before 
deciding.) 

2.  In  what  respects  do  these   corpuscles  differ 

from  those  found  in  frog's  blood  ? 


STUDY   OF   THE  HEART,  45 


29.    Study  of  the  Heaet. 

Materials :  Sheep's  heart  dissected  according  to  tlie  directions  given 
in  Martin's  "Briefer  Course,"  pp.  211-315  (Edition  1895),  pp.  363- 
369  (Edition  1898). 

A.  Using  the    descriptivG    terms    anterior   and   pos- 

terior, dorsal  and  ventral,  right  and  left  (with 
reference  to  the  animal),  locate  the  following 
structures  in  the  heart,  giving,  when  possible, 
the  number  of  each  : 

1.  Auricles.  5.  Mitral  valve. 

2.  Ventricles.  6.  Papillary  muscles. 

3.  Semilunar  valves.      7.  Chordae  tendinese. 
4  Tricuspid  valve. 

B.  Name  the  chamber  of  the  heart  with  which  each  of 

the  following  blood-vessels  is  connected : 

1.  Aorta.  3.  Pulmonary  veins. 

2.  Pulmonary  artery.     4.  Venae  cavse. 

C.  State  all  the  differences  which  you  note  between — 

1.  Dorsal  and  ventral  surfaces  of  the  heart. 

2.  Anterior  and  posterior  ends  of  the  heart. 

3.  Auricles  and  ventricles. 

4.  Largest  veins  and  largest  arteries. 

5.  Mitral  and  tricuspid  valves. 

6.  Mitral   and   tricuspid  valves   and   semilunar 

valves. 

D.  Enumerate  the   differences  between  the  right  and 

left  sides  of  the  heart. 


46  LABORATORY  EXERCISES. 


30.    Circulation  of  the  Blood  in  the  Tail  of  the 

Tadpole,  t 

Cut  a  hole  a  half-inch,  square  near  the  end  of  a  piece  of  thin  board 
three  inches  long  and  one  inch  wide  ;  glue  a  thin  cover-glass  over  the 
hole.  Cover  the  rest  of  the  piece  of  vrood  with  absorbent  cotton 
soaked  in  water.  Lay  a  live  tadpole  on  the  cotton,  placing  the  tip  of 
the  tail  on  the  cover-glass.  Lay  a  cover-glass  on  top  of  the  tail,  and 
fasten  cheesecloth  over  the  animal  to  keep  it  in  place.  Keep  a  plen- 
tiful supply  of  moisture  about  the  animal,  by  allowing  the  end  of  the 
strip  of  cloth  to  dip  into  a  dish  of  water.  Examine  the  tip  of  the 
tail  with  a  compound  microscope  magnifying  about  75  diameters. 

1.  At  the  highest  focus  note  the  epithelial  cells 

forming  the  outside  layer  of  the  body  cov- 
ering.    What  is  their  shape  ? 

2.  What  is  the  shape  of  the  dark  pigment-cells 

seen  just  beneath  the  epithelial  cells  ? 

3.  Focus   still  lower  and  study  the  flow  of  the 

blood  in  the  small  capillaries. 

a.  Is  the  current  steady  in  all  the  blood- 
vessels which  you  see  ? 

h.  Do  the  red  corpuscles  alter  in  shape  as 
they  move  along? 

c.  Can  you  distinguish    any  colorless  cor- 

puscles ? 

d.  Draw  a  small  area  of  the  tail,  represent- 

ing the  course  of  the  capillaries.  In- 
dicate by  arrows  the  course  of  the 
blood  in  each  capillary. 

Note. — If  tadpoles  cannot  be  obtained,  the  web  of  a  frog's  foot 
may  be  examined  after  confining  the  frog  on  a  larger  piece  of  board 
than  that  described  above. 


THE   PULSE   IN   THE   PUFIL'S    OWN  BODY.      47 


31.    The  Pulse  in  the  Pupil's  own  Body.* 

To  take  tlie  pulse  place  the  forefinger  of  the  left 
hand  on  the  radial  artery  of  the  right  hand  at  the 
lower  end  of  the  radius  bone  on  the  palm  side. 

A.  Variations  in  the  pulse-beat. 

1.  Make  out  in  your   note-book  a  statement  of 

your  pulse-rate  taken  under  the  following 
conditions  : 

a.  Before  rising  in  the  morning. 

h.  Just  before  eating  breakfast. 

c.  Just  after  breakfast. 

d.  Just  after  some  violent  exercise. 

2.  What  is  your  conclusion  from  these  observa- 

tions ? 

B.  Find  your  pulse  in  the  following  places  on  your 

body,  locating  each  with  reference  to  the  bones 
of  the  skeleton  : 

1.  On  the  side  of  the  head  in  front  of  the  ear. 

Trace  this  artery  as  far  as  possible. 

2.  On  the  back  of  the  head  near  the  top  of  the 

neck. 

3.  On  the  side  of  the  lower  jaw. 

4.  In  the  hollow  back  of  the  knee-joint. 

5.  On  the  ankle. 


48  LABORATORY  EXERCISES. 

32.    Properties  of  Carbon.* 

Materials  :  Matcli,  meat,  flour,  egg  ;  alcoliol-lamp. 

A.  Strike  a  match  and  allow  it  to  burn  until  the  wood 

is  charred.     Extinguish  the  flame. 

1.  What  is  the  appearance  of  the  substance  (car- 

bon) which  is  left  ? 

2.  Hold    it   in   the   flame    of    an   alcohol-lamp. 

What  change  takes  place  in  the  carbon  ? 
<  3.  What  kind  of  substance  is  left  ?     Heat  this  as 
hot  as  jou  can.     Describe  any  changes. 
4.  What  is  one  method  of  showing  the  probable 
presence  of  carbon  in  a  substance  ? 

B.  Scorch  some  meat,  some  flour,  and  some  egg. 

1.  Do  they  contain  any  carbon  ?     Why  do  you 

think  so  ? 

2.  How  is  the   human  body  supplied  with   new 

portions  of  the  element  carbon  ? 

33.    Tests  for  Carbon  Dioxide. 

Materials  :  Splinter  of  wood  ;  bottle  and  stopper  ;  lime-water. 

A.  Insert  one  end  of  a  splinter  of  wood  in  the  cork  ; 
light  the  splinter,  place  it  in  the  bottle  and  cork 
tightly. 

1.  Record  your  observations. 

2.  Insert   a    glowing  stick  ;    result  ?     (The   hot 

carbon  has  united  with  the  oxygen  of  the 
air,  forming  carbon  dioxide.) 


TEMPERATURE    OF   THE   BODY.  49 

B.  Pour  a  small  quantity  of  clear  lime-water  into  the 
bottle  in  which  the  stick  was  burned,  stopper  the 
bottle  and  shake. 

1.  What  change  do  you  notice  in  the  lime  water  ? 

2.  State   the  method   of  testing   for  carbon  di- 

oxide. 


34.    Temperature  of  the  Body.* 

A.  Place  the  bulb  of  a  chemical  thermometer  beneath 

the  tongue,  closing  the  lips  over  it. 

1.  To  what  point  does  the  mercury  rise  ? 

2.  Is  the    temperature  which   you  have  deter- 

mined the  same  as  that  found  by  the  other 
pupils? 

3.  Take  your  body  temperature  on  a  cold  day, 

then  on  a  warm  day ;    do  you  notice  any 
difference  ? 

4.  Determine  whether  the  body  temperature  is 

the  same  after  violent  exercise  as  it  is  be- 
fore. 

B.  Production  of  heat. 

1.  How  was  heat  produced  in  experiment  32  ? 

2.  How  is  heat  produced  in  your  body  ? 

3.  Is  light  produced  in  the  human  body  (as  in 

32)? 


50  LABORATORY  EXERCISES. 


35.  Action  of  the  Diapheagm  and  the  Lungs. f 

Procure  a  bell  jar  with  an  opening  at  the  top  for  a  stopper.  Place 
a  marble  in  the  centre  of  a  sheet  of  rubber,  tie  the  rubber  about  it, 
and  stretch  the  sheet  of  rubber  over  the  larger  end  of  the  bell  jar, 
tying  tightly.  Secure  a  rubber  stopper  (provided  with  two  holes) 
which  will  fit  the  opening  in  the  top  of  the  bell  jar.  Tie  a  toy  bal- 
loon to  the  end  of  a  glass  tube  and  pass  the  latter  through  one  of  the 
holes  in  the  rubber  stopper.  Through  the  other  hole  pass  a  glass 
tube,  attaching  to  the  upper  end  a  piece  of  rubber  tubing  closed  with 
a  claAp.  Insert  the  rubber  stopper  in  the  opening  at  the  top  of  the 
bell  jar  with  the  toy  balloon  within  the  jar. 

The  balloon  represents  a  lung  ;  the  glass  tube  to  which  it  is  tied, 
the  windpipe  ;  while  the  bell  jar  itself  represents  the  chest-cavity, 
and  the  sheet  rubber  the  diaphragm. 

A.  Exhaust  some  of  the  air  from  the  bell-jar  by  apply- 

ing the  mouth  to  the  rubber  tubing,  and  then  re- 
place the  clamp. 

1.  Is  the  pressure  of  air  greater  now  within  the 

bell  jar  or  without  ? 

2.  What  is  the  effect  on  the  sheet  rubber  of  re- 

moving air  from  within  the  jar?     Explain. 

3.  How  is  the  toy  balloon  affected  ?     Why  ? 

B.  Seize  the  marble  tied  into  the  sheet  of  rubber  and 

make  the  latter  move  up  and  down. 

1.  Does  the  air  within  the  bell  jar  have  more  or 

less  room  when  the  rubber  is  pulled  down  ? 

2.  Is  the  pressure  within  the  glass  jar  greater 

or  less   than  when  the  rubber  diaphragm 
was  pushed  up  into  the  glass  bell  jar  ? 

3.  What  is  the  effect  on  the  rubber  balloon  of 

thus  increasing  the   size  of  the   cavity  in 
which  the  balloon  is  hung  ?     Why  ? 


CIRCULATION    OF  AIR   IN  SCHOOLROOM.        51 

C.  Application  to  the  action  of  human  diaphragm  and 
lungs. 

1.  In  what  respects  does  this   model  illustrate 

the  process  of  inhaling  and  exhaling  air  in 
our  own  bodies  ? 

2.  In  what  respects  does  the  model  fail  to  illus- 

trate the  process  of  respiration  ? 


36.  Circulation  of  Air  in  ScHOOLROOM.f 

Materials  :  Concentrated  hydrocliloric  acid,  concentrated  ammonia; 
evaporating-dishes. 

Pour  into  an  evaporating-dish  some  concentrated 
hydrochloric  acid ;  into  another  dish  pour  some  con- 
centrated ammonia. 

A.  Bring  the  two  dishes  near  together. 

1.  What  is  the  effect  ? 

2.  Place  the  two  dishes  near  the  hot-water  or 

steam-pipes.     Describe  the  course  of  the 
fumes. 

3.  Place  the  dishes  near  the  opening  to  a  venti- 

lator.    What  course  do  the  fumes  take  ? 

4.  Draw  a  diagram  of  the  room  and  indicate  by 

arrows   the   course   of  the    moving  air  as 
demonstrated  by  the  fumes. 

B.  Open  a  window,  and  place  the  two  dishes  near  a 

steam-pipe  near  the  window. 
1.  Does  the  moving  air  take  the  same  course  as 
before  ? 


52  LABORATORY  EXERGI8E8. 

2.  Does  the  open  window  help  or  retard  the 
ventilation  of  the  room? 

Note, — Gunpowder  or  flash-paper  may  be   used  instead   of   the 
acid  and  ammonia. 


37.  Inspired  and  Expired  Air. 

Materials:  Thermometer,  bottle  fitted  as  described  in  C  below  ; 
lime-water. 

A.  Difference  in  temperature. 

1.  Note  on  a  thermometer  the  temperature  of 

the  air  in  the  room. 

2.  Breathe  for  a  few  seconds  on  the  bulb  of  the 

thermometer.     Note  temperature. 

3.  What  is  the  difference  in  temperature  between 

inspired  and  expired  air  ? 

B.  Difference  in  amount  of  moisture. 

1.  Breathe  again  upon  the  polished  bulb  of  the 

thermometer.     Describe  result. 

2.  What  substance  is  thus  shown   to  be  one  of 

the  wastes  excreted  by  the  lungs? 

C.  Differences  in  chemical  composition. 

Secure  a  bottle  fitted  with  a  rubber  stopper 
with  two  holes.  Through  one  hole  in  the  stop- 
per pass  a  glass  tube  (No.  1)  until  it  reaches 
nearly  to  the  bottom  of  the  bottle.  Pass  the 
end  of  another  tube  through  the  other  hole,  al- 
lowing the  tube  to  project  but  a  short  distance 
into  the  bottle  ;  attach  a  piece  of  rubber  tubing 
to  the  upper  end  of  this  tube  (No.  2).  Half-fill 
the  bottle  with  clear-lime  water  and  insert  the 
stopper. 


STUDY  OF  THE  SKIN.  53 

1.  Apply  the  mouth  to  tube  No.  2,  exhausting 

the  air  from  the  bottle.     Describe  result. 

2.  Draw  into  the  lungs  through  the  lime-water 

a  considerable  quantity  of  air  in  this  way. 
Does  any  change  take  place  in  the  lime- 
water  ? 

3.  Does  inspired  air  contain  a  large  amount  of 

carbon  dioxide  ? 

4.  Apply  the  mouth  to  tube  No.  1  (which  passes 

below  the  level  of  the  lime-water).  Expel 
the  air  from  the  lungs  through  the  lime- 
water.  Describe  any  changes  in  the  lime- 
water. 

5.  What  is  your  inference  from  4  ? 

D.  Name  three  differences  between  inspired  and  ex- 
pired air. 


38.   Study  of  the  Skin.* 

Materials:  Clean  needle  ;  printer's  or  mimeograph  ink. 

A.  Epidermis. 

1.  Wash  the  hands  thoroughly  in  warm  water, 

then  dry  them  ;  rub  together  the  palms 
and  fingers  of  both  hands  briskly  for  a 
moment.  What  do  you  see  on  your  hands 
as  the  result  ?  (This  material  was  a  part 
of  your  non-living  epidermis.) 

2.  Run  the  point  of  a  clean  needle  beneath  the 

thin  outer  layer  of  the  skin  on  the  palm  of 

the  hand. 

a.  Does  the  needle  cause  blood  to  flow  ? 


54  LABORATORY  EXERCISES. 

Is  the  outer  layer  of  skin  (epidermis) 
supplied  with  blood-vessels  ? 
K  Does  the  insertion  of  the  needle  cause 
any  pain?  Can  you  feel  the  point  of 
the  needle  touch  the  skin?  Would 
you  infer  that  nerves  entered  the  epi- 
dermis or  not  ? 

3.  In  what  regions  of  the  surface  of  the  hand 

is  the  epidermis   thickest  ?     How  do  you 
know  ?     In  what  region  is  it  thinnest  ? 

4.  Press  the  tip  of  the  forefinger  on  a  piece  of 

cloth  covered  with  some  thick  ink  (print- 
er's ink  or  mimeograph  ink  is  best),  then 
press  the  finger-tip  on  a  page  in  your  note- 
book.    Study  the  impression  made. 
a.  Are  the  black  lines  (made  by  the  ridges 
on  the  finger)  all  of  the  same  width  ? 
Are  they  all  parallel  to  one  another? 
h.  In  the  same  way  take  the  impression  of 
the  tips  of  your  other  fingers  and  of 
your  thumb.     In   what   respects    do 
these  various  impressions  differ  ? 

c.  Where   else  on  your  hand  can  you  see 

similar  ridges  ? 

d.  What   other   lines    are    visible    on    the 

palm  of  the  haud  ? 
B.  Hair. 

1.  On  what  portions  of  the  hand  is  hair  found  ? 

Where  is  it  wanting? 

2.  Compare    the   hair   on   the   surface    of   your 

hand  with  that  on  the  hand  of  an  older 
person.     What  difference  do  you  note  ? 


STUDY  OF  THE  SKIN.  65 

3.  Do  blood-vessels  run  into  the  hair?    How  do 

you  know? 

4.  Which   part   of   the    hair   is    supplied   with 

nerves  ?     How  do  you  know  ? 

C.  Nails. 

1.  What  different  areas  do  you  notice  in  your 

thumb-nail?  How  do  they  differ  in  ap- 
pearance ? 

2.  Make  a  drawing  of  your  thumb-nail,  showing 

these  different  regions. 

3.  Scrape  off  a  little  of  the  outer  surface  of  the 

nail ;  does  this  cause  blood  to  flow  ?  Are 
nails  supplied  with  blood-vessels  ? 

D.  Deeper  layers  of  the  skin. 

1.  With  the  thumb  and  forefinger  of  the  right 

hand  grasp  a  portion  of  the  skin  on  the 
back  of  the  left  hand.  Can  you  lift  the 
skin  from  the  muscles  and  tendons  lying 
below  ? 

2.  In  the  same  way  determine  whether  the  skin 

on  the  palm  of  the  hand  and  on  the  fingers 
is  closely  or  loosely  attached  to  the  under- 
lying tissue.  What  do  you  find  to  be 
true  ? 

3.  Determine  the  effect  of  pushing  a  clean  nee- 

dle point  a  little  distance  into  the  tissue 
lying  beneath  the  epidermis. 

(a)  Is  the   under   skin   (dermis)   supplied 

with   blood-vessels  ?       How   do  you 
know  ? 

(b)  Is   the   dermis   supplied   with   nerves  ? 

How  do  you  know  ? 


56  LABORATORY  EXERCISES. 

E.  Blood  system  in  the  skin. 

1.  Press  the  finger  of  the  right  hand  on  the  back 

of  the  left  hand  ;  quickly  remove  the  fin- 
ger. What  difference  do  you  note  in  the 
color  of  the  spot  pressed  and  in  the  skin 
about  this  spot  ?  Give  an  explanation  of 
this  difference. 

2.  From  the  preceding  experiment  can  you  ex- 

plain the  cause  of  sudden  paleness  in  the 
face? 

3.  State  the  difference  in  the  relative  quantity 

of  blood  flowing  through  the  cheek  when  it 
is  flushed  and  when  it  is  pale.  ^ 


39.  Study  of  the  Kidney  of  the  Sheep. 

Materials  :  Fresh  kidneys  of  slieep  or  pig  in  capsule,  prepared  for 
tlie  pupil  as  follows  :  Slit  the  capsule  on  convex  side  enough  to  allow 
the  kidney  to  be  removed;  cut  the  kidney  from  the  convex  border 
toward  the  hilum  sufficiently  to  open  up  the  cavity  within ;  replace 
the  kidney  within  the  capsule  ;  probe. 

A.  Exterior  of  the  kidney. 

1.  Describe  the  capsule  by  which  the  kidney  is 

surrounded. 

2.  Carefully  remove  the  kidney  from  the  cap- 

sule, taking  care  not  to  tear  the  latter. 
Where  is  the  capsule  attached  to  the  kid- 
ney ? 

3.  What  is  the  shape  of  the  kidney  ? 

4.  What  is  the  color  of  the  kidney.     Why  ? 


STUDY  OF  THE  KIDNEY  OF  THE  SHEEP.  57 

5.  How  many  tubes  can  you  find  connected  with 
this  organ  ?  Can  you  suggest  the  use  of 
any  of  these  tubes?  (The  depression  in 
the  kidney  to  which  the  tubes  pass  is 
called  the  hilum.) 
B.  Gross  structure  of  the  kidney. 

1.  Pull  apart  the  halves  of  the  kidney  sufficiently 

to  look  within. 

2.  What  is   the   shape   of  the   cavity   near   the 

hilum  (sinus  of  the  kidney)  ? 

3.  By  means  of  a  probe  locate  the  tube  (ureter) 

which  passes  out  from  this  cavity. 

4.  The  layer  on  the  outside  of  the  kidney  sec- 

tion is  called  the  cortical  layer. 

a.  Does  this  layer  anywhere  reach  down 

to  the  sinus? 
h.  What    characteristics    distinguish     the 

cortical  layer  from  the  rest  of  the  solid 

portion  of  the  kidney  ? 

5.  The  bodies  which  form  the  medullary  portion 

of  the  kidney  within  the  cortical  layer  are 
called  the  pyramids  of  Malpighi. 

a.  AVhy  is  the  name  pyramid  given  to  them  ? 

b.  Do  these  pyramids  project  into  the  sinus 

of  the  kidney  ? 

c.  Press  one  of  the  pyramids  of  Malpighi. 

Can  you  see  any  substance  ooze  out  ? 


58  LABORATORY  EXERCISES. 


40.  Study  of  Excretion.* 

A.  Excretion  from  sensible  perspiration. 

1.  Find  the  exact  weight  of  your  body  imme- 

diately after  breakfast.     Record  the  figure. 

2.  Exercise  vigorously  for  several  hours  without 

eating  or  drinking. 

3.  Find  again  the  weight  of  the  body.     Do  you 

note  any  difference  in  weight  ? 

B.  Excretion  from  insensible  perspiration. 

1.  Lay  the  palm  of  your  hand  (when  your  body 

feels  cool)  on  a  cold  mirror.  What  evi- 
dence do  you  find  of  the  activity  of  the 
skin? 

2.  Lay  the  back  of  your  hand  on  the  mirror. 

a.  Do  you  find  any  difference  between  the 
amount  of  perspiration  from  the  palm 
and  from  the  back  of  the  hand? 

h.  Study  your  hand  on  a  hot  day  and  an- 
swer the  same  question. 

41.  Sensations  of  Touch.* 

Materials  :  Pen  and  ink,  pin,  ruler,  pair  of  scissors. 

A.  Blindfold  a  person,  touch  lightly  some  portion  of 
his  body  with  a  pen  dipped  in  ink,  and  ask  him 
to  point  out  with  a  pin  the  point  touched,  as 
soon  as  you  have  removed  the  pen. 
1.  Measure  the  distance  with  a  ruler  between 
the  ink-dot  and  the  point  touched  with  the 
pin.     E-ecord  result  as  directed  below  in  4. 


SENSATIONS  OF  TOUCH. 


69 


2.  Try  the  experiment  several  times  on  the  same 

region  of  the  body.     Do  the  results  agree  ? 

3.  Try  the  experiment  on  different  parts  of  the 

body. 

4.  Record  results  in  tabular  form  as  follows  : 


Part  of  body  experimented  upon. 


Distance  between  points. 


1st  trial.        2d  trial 


3d  trial. 


B.  Apply  lightly  the  points  of  a  pair  of  scissors  (sep- 
arated about  a  quarter  of  an  inch)  to  the  palm 
of  your  hand. 

1.  Can  the  points  be  felt  as  two,  or  do  they  feel 

as  one  ? 

2.  Separate  the  points  of   the  scissors   a   little 

more  than  a  quarter  of  an  inch,  and  apply 
again.  At  what  distance  apart  can  the 
points  be  felt  as  two  ? 

3.  In  the   same  way  determine  at  what  distance 

apart  the  points  can  be  felt  as  two  on  the 
tip  of  the  middle  finger,  on  the  tip  of  the 
tongue,  on  the  back  of  the  neck,  on  the  back 
of  the  hand. 

4.  Becord  your  results  in  tabular  form  as  fol- 

lows, placing  the  smallest  distance  first, 
and  arranging  the  distances  in  ord^  from 
smallest  to  greatest. 


Part  of  body  experimented  upon. 


Distance  between  points. 


5.  Apply  the  points  of  the  scissors  at  the  upper 
part  of  the  arm,  near   the    elbow,  at   the 


60  LABORATORY  EXERCISES. 

wrist  and  on  the  palm,  noting  at  what  dis- 
tance apart  the  points  are  felt  as  two. 
a.  Is  the  distance  greater  as  jow.  approach 
the  shoulder  or  as  you  near  the  hand  ? 
h.  Does  it  make  any  difference  whether  the 
points  are   applied  in  transverse  or  in 
longitudinal  axis  of  the  arm  ? 
C.  Cross  the  middle  finger  of  the  hand  over  the  fore- 
finger,   and  rub    the   tips   of   these  two  fingers 
against  the  point  of  your  nose  at  the  same  time. 
What  impression   do  you   receive  in  regard  to 
your  nose  ? 

» 

42.  Sensations  of  Taste  and  Smell.* 

Materials:  Potato,  onion,  apple,  spices,  flavoring  extracts,  sugar, 
salt,  mustard,  quinine  solution,  vinegar. 

A.  Flavors  of  substances. 

1.  Secure  a  bit  of  potato,  a  bit  of  onion,  and  a 

bit  of  apple  ;  close  your  eyes  and  hold  your 
nose  tightly ;  place  each  of  the  three  in 
your  mou-th  successively.  Can  you  dis- 
tinguish by  taste  one  piece  from  the  others  ? 

2.  Keeping  the   eyes   closed,  repeat  the  experi- 

ment without  holding  the  nose. 

a.  Can  the  foods  be  distinguished  now  ? 

h.  What  do  these  experiments  teach  you  in 
regard  to  the  real  nature  of  what  is 
commonly  thought  to  be  the  taste  of 
certain  foods? 

c.  Why  are  many  foods  tasteless  to  a  per- 
son with  a  cold  in  the  head? 


SENSATIONS  OF  TASTE  AND   SMELL. 


61 


d.  What    method    of   taking    disagreeable 
medicines  is  suggested  by  these    ex- 
periments ? 
3.  Close  your  eyes  and  hold  your  nose  ;  experi- 
ment  with    spices,    sugar,    salt,    mustard, 
quinine   solution,  vinegar,   j^eppermint,  va- 
nilla, etc.     Record  your  results  as  follows  : 


Substances  distinguished  by- 
taste  alone. 


Substances  distinguished  by 
taste  and  smell. 


B.  Wipe  the  tongue  dry  and  place  upon  it  a  bit  of 
sugar. 

1.  Can  the  sugar  be  tasted? 

2.  To   what  condition  must  foods  be  brought  in 

order  to  be  tasted  ? 

3.  What  use   of  the   saliva   in  the  mouth  does 

this  suggest  ? 

4.  Give  a  reason  which  may  explain  why  sand  is 

tasteless  ? 
0.  Localization  of  taste  sensations  on  the  tongue. 

1.  Place  a  bit  of  sugar  on  the  tip  of  the  tongue  ; 

another  bit  on  the  back  of  the  tongue. 

a.  In  which  case  is  the  sweet  taste  more 
distinct  ? 

h.  Determine  whether  sweet  substances 
are  tasted  more  distinctly  along  the 
middle  of  the  tongue  or  at  the  edge. 

2.  By  using  a  bit  of  salt  determine  in  the  same 

way  what  region  of  the  tongue  is  most  af- 
fected by  saline  substances. 


62  LABORATORY  EXERCISES. 

3.  Prepare  a  strong  solution  of  quinine  by  dis- 

solving sulphate  of  quinine  in  water  by  the 
aid  of  sulphuric  acid.  Determine  what 
portion  of  the  tongue  is  most  sensitive  to 
bitter  substances  ;  the  portion  which  is  least 
sensitive. 

4.  Test  the  various  portions  of  the  tongue  with 

vinegar. 

5.  Eecord  your  results  as  follows  : 


Kind  of  substance. 

Part  most  affected. 

Part  least  affected. 

Sweet 

Sour 

Bitter 

Salt 

• 

43.  Study  of  Yeast.* 

Materials  for  home  work  :  Compressed  yeast,  molasses  ;  two  pint 
bottles,  small  bottle  ;  refrigerator  ;  stove  ;  thermometer. 

Materials  for  class  demonstrations  :  (A,  9,  10,  D)  ;  Flask,  rubber 
cork  (two  boles) ;  U-tube,  test-tube ;  chemical  thermometer ;  glass- 
and  rubber-tubing ;  water  bath ;  condenser ;  compound  microscope 
(500  diameters),  slide ;  cover-glass ;  lime-water,  eosin  or  methyl 
violet. 

A.  Study  of  the  growth  of  yeast. 

Mix  about  an  eighth  of  a  cake  of  compressed 
yeast  in  a  tablespoonful  of  water  and  stir  until  a 
smooth  thin  mixture  is  formed.  Add  this  to 
about  a  half-pint  of  water  in  which  a  tablespoon- 
ful of  molasses  has  been  dissolved.  Place  this 
mixture  in  a  wide-mouthed  bottle  which  holds 
about  a  pint;  stopper  very  loosely. 


STUDY  OF   YEAST.  63 

1.  State  in  your  note-Look  the  color  of  tlie  mix- 

ture.    Does  it  appear  clear  or  muddy  ? 

2.  What  is  the  smell  and  taste  of  tlie  mixture  ? 

3.  Place  the  liquid  where  the  temperature  is  70° 

to  90°  F.     Determine  the  exact  temperature 
by  the  use  of  a  thermometer,  and  record  it. 

4.  At  the  end  of  several  hours  examine  the  liquid. 

What  evidence  is  there  that  the  yeast  is 
''  working  "  ? 

5.  Determine  the  effect  of  temperature  on  the 

working  of  yeast  in  the  following  manner  : 
a.  Shake  up  the  mixture  when  it  is  working 
well,  and  pour  some  off  into  a  small 
bottle ;  immerse  the  latter  up  to  its 
neck  in  ice-water  for  an  hour,  or  place 
it  in  a  refrigerator. 

(1)  What  is  the  effect  on  the  activity 

previously  noticed  in  the  liquid  ? 

(2)  Warm  the  liquid  again  to  the  tem- 

perature of  the  room  and  record 
result. 

(3)  Yeast  is  a  plant.    Has  it  been  killed 

by  the  cold  ?       Give  reason  for 

your  answer. 
h.  Fill  the  small  bottle  again  with  some 
more  of  the  working  yeast  mixture  ; 
place  it  on  the  stove  and  boil  it,  taking 
care  not  to  break  the  bottle.  Allow 
the  mixture  to  cool  to  the  temperature 
of  the  room. 
(1)  What  effect  does  boiling  have  on 

the  activity  of  the  yeast? 


64  LABORATORY  EXERCISES. 

(2)  Keep  tlie  mixture  for  a  day  or  two. 
Was  the  yeast  killed  by  the  heat  ? 
c.  Summary. 

(1)  What  temperature  do  you  find  to 

be  most  favorable  for  the  growth 
of  yeast  ? 

(2)  What  IS  the  effect  of  extreme  cold  ? 

(3)  What  is  the  effect  of  a  high  degree 

of  heat  ? 

6.  At  the  end  of  24  hours  smell  the  mixture  of 

molasses  and  yeast  remaining  in  your  large 
bottle.  How  does  it  differ  from  that  ob- 
served in  2  ? 

7.  Taste  of  the  liquid  at  the  same  time.     Com- 

pare with  result  obtained  in  2. 

8.  What  differences  do  you  note  in  the    color 

or  in  the  general  appearance  of  the  mixture 
since  the  experiment  was  begun  ?  (Com- 
pare with  observations  in  1.) 
1 9.  Pour  some  of  the  yeast  mixture  which  is 
working  well  into  a  glass  flask.  Insert  a 
rubber  cork  in  the  mouth  of  the  flask 
through  which  passes  one  arm  of  a  U-tube. 
Half-fill  a  test-tube  with  lime-water.  Al- 
low the  free  end  of  the  U-tube  to  dip  below 
the  surface  of  the  lime-water.  Be  sure  all 
the  connections  are  tight.  Set  the  appara- 
tus aside  in  a  warm  place  for  a  few  hours. 
a.  What   change   has  taken    place   in   the 

lime-water  ? 
h.  What    kind  of   gas  is  produced  by  the 

growth  of  yeast  ? 


STUDY  OF   YEAST.  65 

tlO.  Pour  into  another  flask  some  of  the  yeast 
mixture  which  has  been  working  for  some 
time.  Procure  a  rubber  stopper  with  two 
holes.  Through  one  hole  pass  the  bulb  of 
a  chemical  thermometer  so  that  it  reaches 
half-way  down  to  the  bottom  of  the  flask. 
Through  the  other  hole  pass  a  glass  tube, 
allowing  it  to  project  just  inside  the  flask. 
Connect  this  glass  tube  with  rubber  tubing 
to  a  condenser  (used  in  distillation).  Place 
the  flask  over  a  water-bath,  and  keep  the 
temperature  at  the  point  where  the  ther- 
mometer registers  78°  C.  Collect  the  liquid 
which  comes  from  the  condenser, 
a.  What    is    the    smell    and   taste    of   the 

liquid  ? 
h.  Apply  a  lighted  match  to  a  little  of  it. 

Will  it  burn  ? 
c.  What  kind  of  substance  is  formed  when 
yeast   "  works,"  or  when  fermentation 
takes  place  ? 
B.  Into  a  half-pint  of  water  put  a  spoonful  of  the  thin 
yeast  mixture  (of  yeast  and  water) ;   set  aside  in 
a  warm  place  beside  the  other  mixture.     Exam- 
ine at  the  end  of  24  hours. 

1.  Do   you  see   any  evidence   of  activity  in   the 

mixture  ? 

2.  What  kind  of  substance  was  present  in  the 

preceding  experiments  which  is  absent  in 
this  experiment  ? 

3.  What  do  you  infer  from  this  experiment? 


66  LABORATOBT  EXERCISES. 

C.  Summary. 

1.  What  conditions  are  necessary  for  the  rapid 

growth  of  yeast  ? 

2.  What  changes  are  caused  by  the  yeast  in  a 

mixture  in  which  it  is  growing  ? 

3.  What  substances  are  produced  by  the  growth 

of  yeast  ? 

D.  Microscopic  study  of  yeast.     (In  class.) 

By  means  of  a  pipette  put  a  drop  from  the  bot- 
tom of  a  yeast  mixture  on  a  glass  slide ;  cover 
with  a  thin  cover-glass,  and  examine  under  the 
high  power  of  the  microscope. 

1.  What  is  the  color  of  the  solid  bodies  (yeast- 

cells)  which  you  see  ? 

2.  Yeast-cells  form  new  cells  by  budding,  the 

bud  (daughter-cell)  usually  remaining  at- 
tached to  the  cell  (mother-cell)  which  pro- 
duced it. 

a.  Draw  a  group  of  cells  showing  a  mother- 
cell  and  two  daughter-cells. 
h.  Draw  a  group  of  cells  showing  a  mother- 
cell,  two  daughter-cells,  and  two  grand- 
daughter-cells. 

3.  Can  you  distinguish  a  nucleus  in  any  of  the 

yeast-cells  ? 

4.  Place  a  drop  of  stain  (eosin  or  methyl  violet) 

on  the  slide  at  the  edge  of  the  cover-glass, 
allowing  it  to  run  beneath  the  glass  to 
stain  the  cells.  Can  you  make  out  any 
further  facts  regarding  the  structure  of 
yeast? 


STUDY  OF  BACTERIA.  67 


44.  Study  of  Bacteria. 

Materials  for  home  work  (C) :  Three  bottles  (two  provided  with 
stoppers),  ice-box,  thermometer  ;  pint  of  milk. 

Materials  for  class-room  work  (A,  B,  D)  :  Flask,  hot- water  filter, 
beaker,  Petri-dishes,  cotton- wool,  needle,  compound  microscope  (500 
diameters)  slide,  cover- glass  ;  60  gr.  gelatin,  1  lb.  lean  beef,  6  gr. 
peptone,  6  gr.  salt,  caustic  potash,  methyl  violet,  corrosive  sublimate 
solution  (1:1000). 

A..  Study  of  the  growth  of  bacteria. 

"  Nutrient  gelatin,  most  useful  for  the  growth 
of  all  kinds  of  bacteria,  is  prepared  in  this  way : 

"  One  pound  of  lean  beef  is  cut  up,  to  it  is 
added  one  pint  of  water,  and  is  kept  boiling  in 
the  digestor  or  any  other  vessel  for  from  half  to 
three  quarters  of  an  hour.  After  having  been 
strained  through  fine  calico  it  is  filtered  through 
paper  into  a  beaker ;  bring  up  by  adding  water 
to  600  ccm. ;  add  to  this  60  grams  of  the  finest 
gold-label  gelatin  cut  up  in  small  pieces,  6  grams 
of  peptone,  and  6  grams  of  common  salt.  Dis- 
solve on  water-bath,  but  do  not  let  the  water 
boil ;  neutralize  with  carbonate  of  soda  or,  better, 
with  liquor  potassse  till  faintly  alkaline  ;  boil 
for  half  an  hour,  filter  by  hot  filter  into  a  ster- 
ile flask  plugged  with  sterile  cotton-wool,  and 
bring  it  up  to  boiling-point,  at  which  it  is  kept  for 
a  few  minutes.  This  can  be  kept  as  stock  gela- 
tin."— Klein,  "  Micro-Organisms  and  Disease," 
Macmillan  <fe  Co.  (For  further  directions  refer  to 
this  or  other  books  on  bacteriology.) 

Pour  some  of  the  nutrient  gelatin  into  several 


68  LABORATORY  EXERCISES. 

Petri  dishes  which  have  been  sterilized,  quickly 
replacing  the  covers  on  the  dishes,  also  the  cot- 
ton plug  in  the  flask.  Number  the  dishes  1,  2, 
etc.,  and  write  date  of  each  part  of  the  experi-. 
ment. 

Keep  some  of  the  dishes  carefully  closed 
throughout  the  experiments.  Label  each  o\ 
these  dishes  *'Not  exposed." 

Open  several  of  the  other  dishes,  exposing  tho 
gelatin  to  the  air  of  the  room  for  one-half  minute. 
Beplace  the  covers,  and  label  each  dish  *'  Ex. 
posed  to  the  air  one-half  minute." 

Open  other  dishes  sufficiently  to  spread  oi) 
the  surface  a  little  of  the  dust  from  the  floor  or 
from  the  street.  Label  each  dish  "  Exposed 
to  dirt." 

Open  a  third  set  of  dishes  of  the  gelatin  and 
pour  on  the  surface  a  very  little  of  the  city  water 
obtained  from  the  school  faucets.  Label  each 
"Exposed  to  city  water." 

Set  aside  the  dishes  where  the  temperature  is 
about  70°  F.  Examine  the  dishes  at  the  end  of  a 
day  or  two. 

1.  Do    you   find   any    differences   between    the 

dishes  which  have  been  exposed  to  the  air, 
the  dirt,  and  the  water,  and  those  which 
have  not  been  exposed  ? 

2.  Draw  a  figure  of  the  dish  you  are  studying, 

representing  carefully  the  form  and  size  oi 
the  spots  (colonies  of  bacteria  or  mould). 

3.  Study   the    same    dish    several    days   later,  ■ 

Make   a   careful   drawing   as   in    2  above. 


STUDY  OF  BACTERIA.  69 

Have  the  colonies  changed  in  size  or  ap- 
pearance since  jour  last  study? 

4.  Describe  the  color  of  the  colonies. 

5.  Do  any  of  the  colonies  appear  to  affect  the 

gelatine  around  them  ? 

B.  Microscopic  study  of  bacteria. 

Carefully  lift  the  cover  from  one  of  the  plates 
of  gelatin  which  has  been  exposed.  Touch  one 
of  the  colonies  of  bacteria  with  the  point  of  a 
needle,  and  then  rub  the  needle-point  on  a  clean 
glass  slide ;  add  a  drop  of  water  to  the  spot 
touched  by  the  needle,  and  cover  with  a  cover- 
glass.  Examine  with  the  highest  powers  of  the 
microscope. 

1.  What  is  the  color  of  the  tiny  bodies  (bacteria) 

which  you  see  ? 

2.  Do  you  find  more  than  one  kind  of  bacteria  ? 

If  so,  what  is  the  shape  of  each  ? 

3.  Do  an}^  of  the  bacteria  seem  to  be  in  motion  ? 

4.  Place  a  drop  of  stain  (methyl  violet  or  eosin) 

at  the  side  of  the  cover-glass  and  allow  it 
to  run  beneath  the  glass,  staining  the  cells. 
Can  you  make  out  any  further  points  of 
structure  in  the  bacteria  ? 

C.  Growth  of  bacteria  in  milk  (at  home). 

Secure  three  clean  bottles  of  about  the  same 
size,  two  of  them  provided  with  stoppers. 

Into  one  of  the  bottles  pour  some  good  fresh 
milk ;  cover  and  place  in  the  ice-box,  or  in  some 
other  cold  place.     Label  the  bottle  "  No.  1." 

Pour  into  the  second  bottle  about  the  same 
amount  of  milk,  and  set  it  aside  in  a  moderately 


70  LABORATORY  EXERCISES. 

warm  place,  leaving  it  uncorked.  Note  the  tem- 
perature by  means  of  a  thermometer.  Label 
"No.  2." 

Clean  the  third  bottle  and  the  cork  in  boiling 
water.  Boil  some  of  the  milk  15  minutes,  and 
pour  it  into  the  bottle  while  hot.  Cork  the 
bottle  and  place  it  beside  the  second  bottle. 
Label  "  No.  3,  Sterilized  milk." 

Examine  the  three  bottles  of  milk  at  the  end 
of  12  hours. 

1.  Do  you  notice  any  difference  in  the  smell  or 

taste  of  No.  1,  No.  2,  and  No.  3  ? 

2.  Boil  the  milk  in  bottle  No.  3  again  ;  clean  the 

bottle  and  cork  in  boiling  water  as  before, 
and  replace  the  milk  in  the  bottle  ;  cork 
the  bottle.  Put  bottle  No.  1  back  in  the 
ice-box  ;  return  bottles  No.  2  and  No.  3  to 
the  place  from  which  you  took  them. 

3.  Examine  all    three  bottles    at   the  end  of   a 

second  12  hours.  Have  any  further  changes 
taken  place  ? 

4.  Carry  out  the  directions  given  in  2  above  a 

second  time.  Repeat  your  examinations  at 
the  end  of  each  successive  12  hours  for 
two  or  three  days,  each  time  boiling  the 
milk  in  bottle  No.  3.  Becord  in  your  note- 
book each  time  the  changes  which  you 
observe  in  each  of  the  bottles. 

5.  The  changes  in  the  milk  are  caused  by  the 

growth  of  bacteria  from  the  air  or  on  the 
bottles  or  stoppers. 


STUDY  OF  BACTERIA.  71 

a.  What  effect   does   a   cold    temperature 

have  on  the  growth  of  bacteria  ? 
h.  What  effect  does  boiling  have    on   the 
growth  of  these  cells  ? 

c.  What  is  the  most  favorable  temperature 

for  the  growth  of  bacteria  ? 

d.  What  effect  do  some  bacteria  have  on 

the  milk  ? 

e.  Compare  the  results  obtained  in  this  ex- 

periment with  those  already  obtained 
in  the  experiment  with  yeast. 
D.  Sterilization. 

Prepare  three  dishes  of  nutritive  gelatin  as 
directed  above. 

Remove  the  cover  from  No.  1,  and  allow  it  to 
remain  exposed  to  the  air  for  several  minutes. 
Label  it  *'  Gelatin  No.  1." 

Remove  the  cover  from  a  second  dish,  expose 
it  as  in  No.  1 ;  then  pour  over  the  surface  a  thin 
film  of  corrosive  sublimate  (1 :  1000).  Replace 
the  cover  and  label  "  Gelatin  No.  2  -[-  Poison." 
Expose  a  third  dish  of  gelatin  to  the  air  for 
the  same  length  of  time  as  in  No.  1  and  No.  2. 
Heat  this  dish  for  a  half-hour  every  12  hours  in 
a  steam  sterilizer  or  over  a  water-bath.  Label 
"  Heated  Gelatin."  Keep  all  three  dishes 
covered,  and  set  them  aside  where  the  tempera- 
ture is  about  70°  F. 

Compare  the  three  dishes  at  the  end  of  three 
days. 

1.  What  differences  do  you    note  between   the 
three  dishes? 


72  LABORATORY  EXERCISES. 

2.  What  is  the  effect  of   the  poison  (corrosive 

sublimate)  on  the  growth  of  bacteria  ? 

3.  What  effect  does  heating  and  cooling  have  on 

the  growth  of  bacteria  ? 

4.  In  what  two  ways  may  a  substance  be  steril- 

ized ? 
E.  From  all  your  experiments  state— 

1.  What  conditions  seem  to  favor  the  growth  of 

bacteria  ? 

2.  What  conditions  seem  to  hinder  the  growth 

of  bacteria  ? 
r.  Practical  questions  in  bacteriology. 

1.  Why  are  fruits  cooked  before  canning? 

2.  Why   should   fruit-jars   be  filled  completely 

before  screwing  on  the  cover  ? 

3.  Why  do  fruit-jars  sometimes  burst  long  after 

being  filled  ? 

4.  Why  is  grass  dried  before  putting  in  the  barn  ? 

5.  Why  are  milk,  meat,  etc.,  put  in  the  refrig- 

erator in  summer-time  ? 

6.  Why  should  the  prohibition  against  spitting 

in  public  places  be  rigidly  enforced  ? 

7.  Why  should  sweeping  be  done  so  far  as  pos- 

sible without  raising  a  dust  ? 

8.  Why  are  hard-wood  floors  more  healthful  than 

carpets. 

9.  Why  should  the  teeth  be  brushed  often  ? 

10.  Why  should  the  refuse  be  removed  from  the 

streets  every  morning  early,  especially  in 
summer-time  ? 

11.  Why    should    sink-drains    be    carefully    in- 

spected ? 


STUDY  OF  THE  MAMMALIAN  SKELETON.       73 

12.  Why  should   wounds   be   carefully  cleansed 

and  dressed  at  once  ? 

13.  Why  are  typhoid  fever,  diphtheria,  and  other 

infectious  diseases  often  better  treated  in 
hospitals  ? 

14.  In   what  ways    do  bacteria  prove    to  be   of 

benefit  to  mankind  ? 

15.  In  what  ways   do   they  prove  to  be  "  man's 

invisible  foes"?  (Read  "The  Story  of 
Bacteria,"  "  Dust  and  its  Dangers,"  "Drink- 
ing-water and  Ice  Supplies,  and  their  Rela- 
tions to  Health  and  Disease,"  by  T.  M. 
Prudden,  M.D.  Published  by  G.  P.  Put- 
nam's Sons.) 


45.  Comparative  Study  of  the  Mammalian  Skeleton. 

(At  tlie  American  Museum  of  Natural  History,  8tli  Ave,  and  77th  St.) 

Note. — The  skeletons  of  the  lion,  horse,  seal,  musk-ox,  sea  lion, 
and  elephant  are  among  those  best  adapted  for  observation. 

A.  Spinal  Column  : 

1.  How  many  vertebrae   are  found  in   the  neck 

(cervical)  region  ? 

2.  How    many  vertebrae    bear  ribs  (dorsal  ver- 

tebrae) ? 

3.  How  many  vertebrae  in  the  lumbar  region  ? 

4.  Can  you  determine  how  many  vertebrae  have 

united  to  form  the  sacrum  ? 

5.  How  many  vertebrae  in  the  tail  (caudal  ver- 

tebrae) ? 


74  LABORATORY  EXERCISES. 

6.  In  what  regions  of   the    spinal   column  are 

curves  noticeable?       How    do   they   differ 
from  ihe  curves  in  the  human  skeleton  ? 

7.  Are  spinous  processes  specially  developed  in 

any  region  ?     Can  you  suggest  any  reason 
for  this  ? 

B.  Bibs  and  sternum. 

8.  How  many  ribs  has  the  animal  ? 

9.  How  many  are  attached  to  the  sternum  ? 

10.  Is  the  sternum  a  single  piece  of  bone  ?     If  not, 

of  how  many  parts  does  it  seem  to  consist? 

C.  Anterior  appendage. 

11.  Can     you     distinguish     a     shoulder  -  blade 

(scapula)  ? 

12.  Has  the  animal  a  collar-bone  (clavicle)  ? 

13.  Is  the  humerus  relatively  long  or  short  com- 

pared with  the  whole  appendage  ? 

14.  What  is  the  relative  size  of  radius  and  ulna  ? 

15.  Is  it  probable    that   rotation   of   the   radius 

about  the  ulna  is  possible  ? 

16.  Is  the  projection  ("  funny-bone  ")  on  radius  or 

ulna  ? 

17.  How  many  wrist-bones  (carpals)  in  the  an- 

terior appendage? 

18.  Does  the  animal  walk  on  the  palm  of  the 

hand  or  on  the  tips  of  the  fingers  ? 

19.  How  many  fingers  (or  toes)  of  anterior  ap- 

pendage does  it  use  ? 

20.  How  many  bones  are  there  in  each  finger  ? 

21.  Is  a  thumb  distinguishable  ? 

22.  What  use   does  the  animal  make  of  the  an- 

terior appendages  ? 


STUDY  OF  THE  MAMMALIAN  SKELETON.        75 

D.  Posterior  appendage. 

23.  Is  a  knee-cap  (patella)  distinguishable  ? 

24.  Wliat  is  the  relative  size  of  tibia  and  fibula  ? 

25.  How  many  ankle-bones  (tarsals)  are  found  in 

the  posterior  appendage? 

26.  How  many  toes   of  the   posterior  appendage 

does  the  animal  use  ? 

27.  Does  the  animal  seem  to  be  adapted  for  swift 

or  for  slow  locomotion  ?     Give  reasons  for 
your  answer. 

E.  Teeth. 

28.  What  is  the  dental  formula  (number  of  in- 

cisors, canines,  grinders  in  each  half -jaw)  ? 

29.  Did  the  animal  probably  eat  animal  or  vege- 

table food  ?     Beason  for  answer. 


46.    Rules    for    the    Use    of    the    Compound 
Microscope. 

I.  To  lift  the  microscope,  always  grasp  it  firmly  by  the 

pillar  beneath  the  stage. 

II.  To  use  the  loio  poiver  objective, 

1.  Place  the  stand  so  the  two  arms  of  the  foot 

face   the   wdndow.     Keep   the  microscope 
out  of  the  direct  sunlight. 

2.  See    that    the  nose-piece  is  in  the   position 

which  will  bring  the  low-power  objective 
over  the  opening  in  the  stage. 

3.  Move  the  tube  up  or  down  by  the  rack  and 

pinion  until  the  lower  end  of  the  low-power 


76  LABORATORY  EXERCISES. 

objective  is  a  little  more  than  a  quarter  of 
an  inch  above  the  level  of  the  stage. 

4.  See  that  the  plane  side  of  the  mirror  is  facing 

the  source  of  light.  Looking  down  through 
the  tube,  move  the  mirror  about  until  the 
field  of  the  microscope  has  the  best  possi- 
ble illumination.  (The  field  of  the  micro- 
scope is  the  lighted  circular  area  which 
appears  when  looking  down  through  the 
tube.) 

5.  Place    the   slide   on   the    stage    (cover-glass 

on  top)  in  a  position  so  the  object  to  be 
examined  is  over  the  centre  of  the  hole  in 
the  stage.  Fix  the  slide  in  place  with  the 
clips. 

6.  Look   through   the   microscope,  and  slowly 

move  the  tube  up  by  turning  the  rack  and 
pinion  until  the  object  is  seen  as  clearly 
as  possible.  Be  careful  never  to  push  the 
tube  down  so  the  objective  touches  the 
slide. 

7.  In    examining   a   slide,    focus    the   tube   by 

means  of  the  fine  adjustment-screw.  When 
the  screw  is  turned  in  a  direction  like  the 
hands  of  a  clock,  the  objective  is  lowered ; 
when  turned  in  the  opposite  direction,  the 
objective  is  raised  from  the  slide. 

III.    To  use  the  high-potver  objective. 

1.  Place  the  slide  upon  the  stage  and  focus 
upon  it  with  the  loiv-power  objective  as 
directed  in  II  above. 


THE  USE  OF  THE   COMPOUND  MWROSGOPE.       77 

2.  Turn  the  mirror  so  the  concave  surface  faces 

upward.  Looking  through  the  tube,  move 
the  mirror  about  until  the  field  of  the 
microscope  has  the  best  illumination. 

3.  Place  the  eye  at  the  level  of  the  stage  and 

carefully  turn  the  nose-piece  so  the  high- 
power  objective  is  brought  into  position 
above  the  hole  in  the  stage.  If  the  lower 
end  of  the  objective  touches  the  cover- 
glass,  turn  the  fine  adjustment-screw  in  a 
direction  opposite  to  that  of  the  hands  of 
a  clock. 

4.  When  the  objective  is   in  position  look  at 

the  object  through  the  microscope,  and 
focus  slowly  with  ih.Q  fine  adjustmenUscreio 
until  the  image  is  clearest.  Take  great 
care  as  directed  in  3  above  to  see  that  the 
objective  does  not  touch  the  cover-glass. 

5.  After  using  the  high-power  objective,  turn 

the  nose-piece  so  as  to  leave  the  low-power 

objective  in  position  over  the  diaphragm. 

IV.  The   pupil    should  learn   to    look    through    the 

microscope  with  both  the  right  and  the  left  eye. 

Both  eyes  should  always  remain  open. 

Y.  Approximate    magnifications   of   the   Bausch   and 

Lomb  microscopes. 

1.  2-inch  objective  with  2-inch  eye-piece  magni- 

fies about  15  diameters. 

2.  2-inch  objective  with  1-inch  eye-piece  magni- 

fies about  30  diameters. 

3.  f-inch  objective  with  2-inch  eye-piece  magni- 

fies about  50  diameters. 


78  LABORATORY  EXERCISES. 

4.  f-inch  objective  with  1-incli  eje-piece  magni- 
fies about  100  diameters. 

6.  -|^-incli  objective  with  2-inch  eye-piece  magni- 
fies about  250  diameters. 

6.  l^-inch  objective  with  1-inch  eye-piece  magni- 
fies about  450  diameters. 


APPARATUS  AND   CHEMICALS  RKQUIRED.        79 

List  of  ArPAEATus  and  Chemicals  required  to 
Supply  a  Class  oe  24 

Articulated  Skeleton,  $25  (may  be  obtained  of  The 
Kny-Sclieerer  Co.,  17  Park  Place,  New  York  City). 

Joint  apparatus  devised  by  Dr.  G.  W.  Fitz  of  Har- 
vard University,  $5  (may  be  obtained  of  H.  Sumner, 
"Wood  Avenue,  Hyde  Park,  Mass). 

The  following  supplies  will  be  furnished  to  schools 
by  Bausch  k  Lomb,  1123  Broadway,  New  York  City, 
at  the  special  prices  quoted.  (The  numbers  and  let- 
ters refer  to  Bausch  &  Lomb's  Catalogue.) 


1  Compound  Microscope,  AABl. 

%rli"   ^ 

24    Magnifiers,   5-10"    diameter, 

QR  

1  Weig^hing  Balance,  No.  7120.. 
24  Evaporatiii°r    Dishes    (porce- 
lain), Xo.  4430,  50  cc. . 

24    Alcohol  Lamps,  No.  3693  c., 

100  cc  

1  Gross  Slides  (3x1"),  No.  7315. 
1  oz.  Round  Cover-glasses,  %!', 

No. 2 

24  Scalpels,  No.  5480 

24  Pairs  Forceps,  straight,  No. 

5S50 

50  Dissecting  Needles,  No.  5950. . 
72  Test-tubes,  150X16  mm.,  No. 

3905 

1   Chemical  Thermometer,  No. 

37353 

1  Lactometer,  No.  3754 

12  Iron  Apparatus  Stands,  No. 

5095,  3  rings 

24  Pieces  Wire  Gauze,  3X3",  No. 

5215 per  lb. 

24  Glass  Stirring-rods.  No.  4566  . 
10  Ft.  Glass  Tubing,  5  mm.,  No. 

4560 .. 

1  Thistle-tube.  No.  40iO,  30  mm. 
24  Beaker  Glasses,  98  mm..  No. 

4395 

1  Glass  Bottle,    3  oz.,  provided 
with  rubber  cork.  2  perfora- 
tions, No.  4320,  cork  No.  5295 
1  Bell  Jar  with  opening  at  the 
top,  180  X  100  mm..  No.  4510. 

1  Piece  of  Sheet  Rubber 

2  Florence  Flasks,  250  cc. ,  No. 
3850  


25  60 

8  00 

13  50 

2  70 

7  50 

0  64 

75 

4  50 

4  50 

1  57 

1  12 

94 

38 

9  00 

38 

90 

38 

09 

3  00 

10 

75 

15 

26 

1  Hot-water  Filter,  No.  4005...  $3  00 
12  Petri  Dishes,    80    mm..    No. 

3802 1  80 


CHEMICALS. 

}4  lb.  Hydrochloric  Acid  (C.P.), 

500  cc 24 

1^  lb.   Nitric  Acid  (cone),  C.P., 

500  cc.  No.  7767 26 

1^   lb.  Ammonia    (cone),   C.P., 

500  cc,  No.  7767 12 

J4  lb.  Sulphuric  Acid,  No.  7769, 

500  cc   24 

1  oz.  Iodine,  No,  7732 38 

5  oz.   Potassium    Iodide,    No. 

7753 1  50 

14  lb.  Ether  Sulphuric,  250  cc. 

No.  7775 82 

5  gr.  Caustic  Potash 12 

5  gr.  Caustic  Soda 12 

100  cc  Lime-water  12 

100  Pieces  of  Red  Litmus-paper, 

2X!4",  No.  7600 08 

4  gr.  Quinine 12 

500  cc.  95^  Alcohol,  No.  7783 51 

100  cc.  Glycerin,  No.  7790 26 

5  gr.  Pancreatin  (Fairchild) ...  06 

5  gr.  Ox-gall 12 

5  gr.  Pepsin  12 

10  gr.  Common  Salt. 05 

1  gr.  Phosphate  of  Lime 12 

10  gr.  Glucose 12 

500  cc.  Fehling  solution,  No.  7776  1  50 

10  gr.  Eosin.  No.  7874  26 

10  er.  diethyl  Violet,  No.  7896. . .  26 

1  lb.  Gelatin,  No.  7847 68 

12  gr.  Peptone .  10 


QP44  P3: 

Pcstbody 
Tiaborat.ory  exercises   in   anatomy 


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